Glossary of botanical terms

Many of the terms used in Wikipedia glossaries (often most) are already defined and explained within Wikipedia itself. However, lists like the following indicate where new articles need to be written and are also useful for looking up and comparing large numbers of terms together. Terms relating to Plant morphology are included here as well as at Glossary of plant morphology. See also List of Latin and Greek words commonly used in systematic names.

This glossary is incomplete; you can help by expanding it: you can also help by adding illustrations that assist an understanding of the terms.

A

ab-
A prefix meaning from, away from, or outside of.
abaxial
The surface of an organ facing away from the axis; e.g. the lower surface of a lateral organ such as a leaf or petal.
abort
To abandon development of a structure or organ.
abscission
shedding of an organ that is mature or aged, e.g. a ripe fruit or an old leaf.
abscission zone
a specialised layer of tissue formed, for example, at the base of a petiole or pedicel that allows the organ to be shed by abscission when it is ripe or senescent.
Acaulescent Welwitschia
acaulescent
An adjective descriptive of a plant that has no apparent stem, or at least none visible above ground. Examples include some species of Agave, Oxalis and Attalea.[1]
accrescent
Increasing in size with age, such as a calyx that continues to grow after the corolla has fallen, for example in Physalis peruviana.
-aceae
The suffix added to the stem of a generic name to form the name of a family.
achene
A dry 1-seeded indehiscent fruit; e.g. in the genus Ranunculus.
acicular
Slender or needle-shaped.
acropetal
Moving from roots to leaves, e.g. of molecular signals in plants.
acrophyll
The regular leaves of a mature plant, produced above the base; usually in contrast to bathyphyll.
acrostichoid
(describing a type of sorus) covering the entire abaxial surface of the frond, usually densely so, as in Elaphoglossum and Acrostichum.
The diatom Actinoptychus senarius is actinomorphic.
actino-
A prefix that indicates a radial form.
actinodromous
(leaf venation) palmate or radially arranged venation with three or more primary veins arising from at or near the base of the leaf, the primary veins reaching the margin or not.
actinomorphic
regular; radially symmetrical; may be bisected into similar halves in at least two planes. Applies e.g. to steles and flowers in which the perianth segments within each whorl are alike in size and shape; compare regular; contrast with asymmetrical, irregular, zygomorphic.
aculeate
Armed with prickles; e.g. the stem of a rose.
acuminate
Tapering gradually to a point.
acute
Sharply pointed; converging edges making an angle of less than 90°; compare obtuse.
ad-
A prefix meaning near or towards. Also meaning added to.
adaxial
The surface of an organ facing towards the axis; e.g. the upper surface of a lateral organ such as a leaf or petal.
adnate
grown or fused to an organ of a different kind, especially along a margin; e.g. a stamen fused to a petal; cf. connate.
adventitious
A structure produced in an abnormal position; e.g. an adventitious bud produced from a stem rather than from the axil of a leaf.
adventive
Introduced accidentally (usually referring to weeds).
aerial
Of the air; growing or borne above the surface of the ground.
aestivation
The arrangement of sepals and petals or their lobes in an unexpanded flower bud; cf. vernation, the arrangement of leaves in a bud.
aff. (affinis)
With affinity to others, akin to; often used for a provisionally recognized but unnamed taxon considered close to that name, perhaps a hybrid or extreme variant.
aggregate fruit
A cluster of fruits formed from the free carpels of one flower, e.g. blackberry; cf. multiple fruit.
agricultural weed
see weed.
alate
having a wing or wings.
albumen
an older name for the endosperm of flowering plants. Except for being a storage tissue for nutrients, it is not at all like the albumen (egg white) of animals.
albuminous
(seeds) containing endosperm.
-ales
Suffix to the stem of a generic name or descriptive name to indicate that it applies to a taxon of the rank of order.
alien
a plant introduced to an area outside its natural range (foreign, exotic, non-native, non-indigenous).
alkaloid
Molecule with a nitrogenous base, many used as drugs; e.g. morphine, quinine, strychnine.
alternate
(as adjective) leaves or flowers borne singly at different levels along a stem includes spiralled parts; or (as preposition) when something occurs between something else, for example stamens alternating with petals; compare opposite.
ament
Synonym of catkin.
amphitropous
When the ovule is bent so that both ends are near each other; cf. anatropous, campylotropous, orthotropous.
amplexicaul
With the base dilated and clasping the stem, usually of leaves.
anastomosing
When veins are joined by cross-veins to form a network.
anatropous
When an ovule is inverted so that the micropyle faces the placenta (this is the most common ovule orientation in flowering plants); cf. amphitropous, campylotropous, orthotropous.
androdioecious
Of plants, having bisexual flowers and male flowers on separate individuals; cf. andromonoecious, polygamodioecious, polygamomonoecious, polygamous.
andromonoecious
of a species, with bisexual flowers and male flowers on the same plant; cf. gynomonoecious
androecium
Male parts of flower; the stamens of a flower collectively; cf. gynoecium. Abbreviation: A. For instance A 3+3 indicates 6 stamens in two whorls.
androgynophore
A stalk bearing both the androecium and gynoecium of a flower above the level of insertion of the perianth.
androgynous
With male and female flowers in the same inflorescence.
andromonoecious
having bisexual and male flowers on the same individual; cf. andromonoecious, polygamodioecious, polygamomonoecious, polygamous.
anemophily
Pollination by wind.
angiosperms
flowering plants; plants with developing seeds enclosed in an ovary.
anisomery
the condition of having a floral whorl with a different (usually smaller) number of parts from the other floral whorls.
anisotomic
branching with branches having unequal diameters, such as a trunk and its branch, compare to isotomic.
annual
A plant that completes its life cycle and dies within one year.
anastomose
branching then rejoining.
anterior
positioned in front of, towards the apex, distal.
anther
Pollen-bearing part of the stamen.
anthesis
1.  (of a flower) the period during which pollen is presented and/or the stigma is receptive.
2.  (of a flowering plant) the period during which flowers in anthesis are present. note: not defined for some cases, such as when pollen is released in the bud.
anticlinal
Pointing up away from or perpendicular to a surface, cf. periclinal.
antrorse
Directed towards or upwards, e.g. of hairs on a stem; cf. retrorse.
apetalous
Without petals.
apex
(plural apices) The tip; the point furthest from the point of attachment.
aphlebia
(plural aphlebiae) Imperfect or irregular leaf endings commonly found on ferns and fossils of ferns from the Carboniferous Period.
apiculate
(Usually referring to a leaf) terminating in a short sharp flexible point; less abrupt than mucronate.
apiphily
A form of pollination whereby pollen is distributed by honey bees.
apo-
A prefix meaning away from, separate, without.
apocarpous
Of a gynoecium consisting with one or more carpels which are free from one another (or almost so); e.g. Ranunculaceae, Dilleniaceae.
apomixis
Reproduction, where viable seed or spores are produced without fertilization. A plant produced in this way is an apomict.
apomorphy
(in cladistics) a "different form" from the form of an ancestor, i.e., an innovation, of use in determining membership in a clade.
appendage
A secondary part attached to the main structure; an external growth that seldom has any obvious function, hence appendiculate.
appendiculate
Having the nature of, or bearing appendage(s).
appressed
Pressed closely, but not fused; e.g. leaves against a stem.
aquatic
Plants whose natural habitat is water: living in or on water for all or a substantial part of the organism's life span, generally restricted to fresh or inland waters.
arachnoid
Cobwebby, from being covered with fine white hairs.
arborescent
Tree-like in growth or general appearance.
arboretum
(plural arboreta) A taxonomically arranged collection of trees.
archaeophyte
An non-native plant that has been present in a geographic area for some time; cf. neophyte.
areolate
Having areoles, being composed of areoles, as an areolate crustose lichen.
areole
(from areola) A space between the threads of a net; e.g. that part of a leaf surface defined by each of the elements of a vein network; as with cacti, the area between the veinlets of a leaf or the region of a cactus bearing the flowers and/or spines. In lichenology, an areole is a polygonal piece of a thallus surface when a crustose lichen it broken up like old dried and cracked paint, or like the polygonal "islands" of dried mud in a dry lake bed.
aril
(adjective arillate): A membranous or fleshy appendage (formed by expansion of the funicle) which partly or wholly covers a seed; e.g. the fleshy outer layer of lychee fruit and as found in Sapindaceae.
aristate
With a stiff, bristle-like awn or tip.
article
A segment of a jointed stem or of a fruit with constrictions between the seeds; an organ part that separates easily from the rest of the organ at a joint or articulation.
articulate
Jointed; separating freely, leaving a clean scar; for example the fronds of certain ferns where they join the rhizome.
ascending
Spreading horizontally, then becoming erect.
ascocarp
The fruiting body (sporocarp) of an ascomycete fungus.
ascomycete
A member of the Ascomycota.
Ascomycota
A division (biology) or phylum of fungi commonly called sac fungi. It is separated from the division Basidiomycota
Infructescence of wild rye, showing prominent awns
Anatomy of awn and bristles on a species of Australian grass
asexual reproduction
reproduction that does not involve gametes; i.e. vegetative reproduction.
asymmetrical
irregular, unequal, lacking any plane of symmetry.
attenuate
Narrowing gradually.
auricle
(adjective auriculate): Ear-shaped lobe.
awn
Long, bristle-like appendage; e.g. terminating or on the back of glumes and/or lemmas of some grass spikelets.
axil
The upper angle between one part of a plant and another; e.g. the stem and a leaf.
axile
On an axis; of a placenta, on the central axis of the ovary.
axillary
Borne in or arising from the axil of a leaf.
axis
the main stem of a whole plant or inflorescence.

B

baculiform
rod-like, longer than wide, c.f. cylindrical
barb
a rear-facing point, as in a fish hook.
barbed
with (barbs pointing in one direction.)
barbellate
with barbed hairs (barbellae)
bark
the protective external layer of tissue on the stems and roots of trees and shrubs; includes all of the living and non-living tissue external to the cambium.
basal
at the base, situated or attached at the base.
basifixed
something attached by its base; e.g. an anther attached to the filament. compare: dorsifixed
basipetal
developing sequentially from the apex towards the base (i.e. with the youngest towards the base); e.g. of flowers in an inflorescence. Also, moving from leaves to roots, e.g. of molecular signals in plants.
bathyphyll
a specialized leaf that is produced at the base of a plant, usually when the plant is immature, and which serves to anchor the plant to a substrate; especially notable in the fern Teratophyllum. (compare: acrophyll).
beak
a prominent pointed terminal projection, especially of a carpel or fruit. adj. beaked
berry
an indehiscent fruit, with the seeds immersed in the pulp, for instance tomato.


bi-
prefix meaning two, for example bisulcate, two sulci or grooves. For other uses, see specific -suffix
biennial
plant which completes its life cycle and dies within the second year; usually also forms a basal rosette of leaves the first year and flowers and fruits the second year.
bifid
forked; cut in two for about half its length. See also trifid.
bifoliate
having 2 leaflets (a type of compound leaf).
bifusiform
fusiform with a pinch in the middle
bilabiate
having two lips; e.g. the form of the petals in many irregular flowers.
bilateral
arranged on opposite sides; e.g. leaves on a stem.
biloculate
having two loculi; e.g. in the anthers.
binomial
making use of names consisting of two words to form the scientific name (or combination) in a Latin form. For example, where the first is the name of the genus to which the species belongs, and the second is the epithet given to that species to distinguish it from others in the same genus.
binomial nomenclature
the system of nomenclature in which the scientific name of a species (and not of a taxon at any other rank) is a combination of two names, the first name being the generic name. The second name is referred to botanically as the specific epithet. Note that the two names constitute the species name, not just the second word.
bipinnate
twice pinnate; for example of a compound leaf with individual leaflets pinnately divided.
bipinnatisect
a pinnatisect leaf with deeply dissected segments.
bisexual
bearing both male and female reproductive organs; usually, flowers with both stamens and carpels; synonymous with hermaphrodite, synoecious, monoclinous. Bisexual flowers only occur on monoecious plants. See also androgynous, monoicous, and Plant reproductive morphology.
bitegmic
(of an ovule), covered by two integuments.
Structure of a biternate compound leaf
biternate
ternate, with each division divided into three
bivalve
having two valves or hinged parts. See also trivalve.
blade
the lamina or flattened part of a leaf, excluding the stalk.
bloom
a fine white or bluish waxy powder occurring on plant parts, usually stems, leaves and fruits. It is easily removed by rubbing.
bole
the trunk of a tree, usually below the lowest branch; cf. canopy.
bract
modified leaf associated with flower or inflorescence, differing in shape, size or colour from other leaves (and without an axillary bud).
bracteate
possessing bracts.
bracteole
small bracts borne singly or in pairs on the pedicel or calyx.
bracteolate
possessing bracteoles (bractlets)
bractlet
bracteole
branchlet
a small branch.
brevideciduous
a plant that loses all of its leaves briefly, so that it is leafless for, e.g., about two weeks.
bristle
(adjective: bristly) straight stiff hair (smooth or with minute teeth) or upper part of an awn (when the latter is bent and has a lower, stouter, and usually twisted part, called the column).
brochidodromous
pinnate leaf venation in which the secondary veins do not terminate at the leaf margin, but are joined in a succession of prominent arcs.
bryophyte
informally, a collective term for mosses, hornworts and liverworts. Formally, these plants are placed in three separate divisions: hornworts (Anthocerophyta), liverworts (Marchantiophyta) and mosses (Bryophyta).
bulb
(adj. bulbiferous), thick storage organ, usually underground, consisting of a stem and leaf bases (the inner ones fleshy).
bulbel
a bulb arising from another bulb.
bulbil
small deciduous bulb or tuber formed in the axil of a leaf or pinna; a means of vegetative propagation.
bulblet
a bulb arising from another bulb; a bulbil.
bullate
surface with rounded or globular blisters.
burr
loosely, a prickly fruit; a rough or prickly propagule consisting of a seed or fruit and associated floral parts or bracts.
buttress root
a root growing from the above-ground stem or trunk, and providing support, as in the case of Ficus macrophylla, the Moreton Bay fig.
byssoid
a growth form of a lichen thallus that is whispy, like teased wool.

C

C, C−, C+
In lichenology, "C" is an abbreviation for the test result of placing 5% solution of calcium hypochlorite or sodium hypochlorite (e.g., household bleach without additives) on the cortex or the medulla of a lichen, to note the change in color, with no reaction noted as "C−", and production of a bright colour noted as "C+".
caducous
falling off early, for example the sepals of poppies, that fall off when the petals begin to open; compare persistent and fugacious.
Dianthus chinensis has a caespitose growth habit.
caespitose
tufted; e.g. the growth form of some grasses.
calcareous
A soil type that is rich in calcium carbonate. A lichen substrate rock type that is largely composed of calcium carbonate.
callose
callous, hardened, thickened.
Callus tissue of tobacco, Nicotiana tabacum growing on a nutrient medium in plant tissue culture
callus
1.  (plural: calli), a protruding mass of tissue.
2.  undifferentiated tissue growth formed in response to wounding; may be grown in vitro.
3.  in orchids, fleshy outgrowths from the labellum which can be variously shaped from papillae to plates
4.  in grasses, a hardened extension from the base of a floret (formed from the rachilla joint and/or the base of the lemma) which may or may not elongate and is often covered in hairs or bristles.
calyciflorous
"calyx flowered", with petals and stamens attached to the calyx
calycophyll
a leaf-like structure formed from a sepal or calyx lobe which enlarges, usually many-fold, before or after anthesis, especially when most of the sepals or calyx lobes retain their original size. More extreme than an accrescent calyx, calycophylls are found in Rubiaceae. cf. semaphyll, pterophyll.
calyculate
having an epicalyx.
calyculus
(1) a cup-shaped structure formed from bracts, (2) in some Asteraceae, a circle of bracts below the involucre.
calyptra
a hood or lid; see operculum.
calyx
(plural calyces) the outer whorl of a flower, usually green; the sepals of one flower collectively.
calyx tube
a tube formed by the fusion of the sepals (calyx), at least at the base.
campanulate
bell-shaped.
camptodromous
pinnate venation in which the secondary veins curve toward the margins, in some cases becoming nearly parallel with them, and not reconnecting with other veins to form loops.
campylotropous
when the ovule is oriented transversely (i.e. with its axis at right angles to its stalk) and with a curved embyro sac; cf. amphitropous, anatropous, orthotropous.
canaliculate
channelled; with a longitudinal groove.
canescent
approaching white in color, as in a leaf covered with white down or wool.
canopy
the branches and foliage of a tree; crown; cf. trunk. Also refers to the protective upper layer of a forest.
capillary
1.  (noun) a tube, pore or passage with a narrow internal cross-section.
2.  (adjective) slender, hair-like.
capitate
with knob-like head; of an inflorescence, with the flowers unstalked and aggregated into a dense cluster; of a stigma, like the head of a pin.
capitulum
a dense cluster of sessile, or almost sessile, flowers or florets; e.g. a flower head in the daisy family Asteraceae. see pseudanthium and pseudanthium.
capsule
a dry fruit formed from two of more united carpels and dehiscing when ripe (usually by splitting into pieces or opening at summit by teeth or pores).
carina
(adjective carinate) see keel.
carinal canal
a longitudinal cavity in the stems of Equisetum and extinct Equisetopsida, coinciding with a ridge in the stem surface.
carpel
the basic female reproductive organ in angiosperms, either consisting of a single sporophyll or a single locule of a compound ovary, with a style and a stigma. The gynoecium is the collective term for all of the carpels of a single flower.
cartilaginous
hard and tough; gristly.
caryopsis
a dry, indehiscent, one-seeded fruit in which the seed coat is closely fused to the fruit wall, as in most grasses.
Casparian strip
a continuous band of suberin in the radial primary cell walls of the endodermis in vascular plant stems and roots that forms a permeability barrier to the passive diffusion of external water and solutes into the vascular tissue.
casual alien
a plant that appears with no apparent human assistance but does not develop a sustained population(s). Plants that persist only by new introductions; cf. alien.
cataphyll
Early leaf forms of plants or shoots, such as cotyledons, bud-scales, rhizome-scales; anatomically they are leaves, but do not develop to perform the usual functions of photosynthetic leaves.
catkin
a spike, usually pendulous, in which the mostly small flowers are unisexual and without a conspicuous perianth; e.g. willows, poplars, oaks and casuarinas. The individual flowers often have scaly bracts; they are generally wind-pollinated. The catkins are usually shed as a unit.
caudate
having a narrow tail-like appendage or tip, e.g. a drip tip, cf. acuminate
caudex (plural: caudices)
Literally the stem of a plant, but also used to mean a rootstock, or particularly a basal stem structure or storage organ from which new growth arises. See also caudiciform
caudiciform
Literally meaning "stem-like" or "caudex-like", is sometimes used to mean "pachycaul", meaning "thick-stemmed".
cauline
borne on an aerial stem, e.g. leaves, flower or fruits (when applied to the latter two organs, usually referring to older stems; = cauliflorous).
cell
1.  basic (microscopic) unit of plant structure, generally consisting of compartments in a viscous fluid surrounded by a wall.
2.  cavity of an anther or ovary.
centrifixed
of a two-branched organ attached by its centre, e.g. a hair, or anther.
cespitose
alternative spelling of caespitose.
chartaceous
with a papery texture.
chamber
cavity of an ovary.
channelled
sunken below the surface, resulting in a rounded channel.
chasmogamous
of flowers that are pollinated when the perianth is open; cf. cleistogamous.
chasmophyte
a plant adapted to growing in crevices or hollows, such as in cliff faces (compare cremnophyte). (From Greek chasma)[2][3]
chimera
an individual composed of two or more genetically different tissues, most commonly as a result of a graft and sometimes within the individual, by mutations and irregularities that occur during cell division.
chiropterophilous
pollinated by bats.
chlorophyll
a green pigment in chloroplasts, essential for photosynthesis.
chloroplast
an organelle present in plant cells that contains chlorophyll.
chlorosis
abnormal lack or paleness of color in a normally green organ.
cilia
(singular cilium, adjective ciliate) generally, hairs more or less confined to the margins of an organ, like eye-lashes; in motile cells, minute, hair-like protrusions which aid motility.
circinate
spirally coiled with the tip innermost; e.g. circinate vernation of the developing fronds of most ferns.
cladode
a photosynthetic stem, often leaf-like and usually with foliage leaves either absent or much reduced; cf. phyllode.
class
the principal category for taxa in a rank between division and order.
clathrate
latticed or pierced with apertures, like a cage.
clavate
club-shaped.
claw
1.  narrow, stalk-like basal portion of petal, sepal of bract.
2.  in Melaleuca, the united portion of a stamen bundle.
cleistogamous
of flowers that self-pollinate and never open fully, or self-pollinate before opening; cf. chasmogamous.
climber
a plant growing more or less erect by leaning or twining on another structure for support, or by clinging with tendrils.
cline
(adjective clinal) continuous morphological variation in form within a species or sometimes between two species.
clone
plants derived from the vegetative reproduction of an individual, all having the same genetic constitution.
coalescent
plant parts fused or grown together to form a single unit.
cochleariform
concave, spoon-shaped.
cochleate
coiled like a snail's shell.
coenobium
An arranged colony of algae that acts like a single organism.
coenocyte
A single cell with multiple nuclei, formed when nuclear division was not followed by cytokinesis.
collenchyma
A specialized tissue consisting of living cells with unevenly thickened cellulose and pectin cell walls that performs a support function in organs such as leaves and young stems that are composed of primary plant tissues.
colleter
a multicellular, glandular hair that usually produces a mucilaginous substance and is located on sepals, stipules, or petioles, or on nearby parts of stems; commonly found on plants in the order Gentianales.
columella
in flowering plants, the central axis of the cone or fruit, e.g. in Callitris.
column
1.  structure extending above ovary and incorporating the style and stamens; gynostemium; e.g. in orchids.
2.  in grasses, the lower, stouter, and usually twisted part of an awn, distinct from the slender upper part or bristle.
columnar
shaped like a column.
commercial name
a name often of no botanical standing and not governed by the ICNCP. The term generally applies to names such as Trademark Names, names covered by Plant Breeders Rights, Patents and Promotional Names; often used to enhance the sale of a plant.
commissure
the seam or face at which two carpels adhere.
community
an assemblage, in nature, of plants that characteristically occur together.
compound
composed of several parts, for instance a leaf with leaflets, a gynoecium with several carpels, or an inflorescence made up of smaller inflorescences.
California Buckeye (Aesculus californica) has a compound palmate leaf, because the leaflets radiate out from a central point.
compound palmate
a compound palmate leaf has leaflets that radiate from a central point (usually at the top of a petiole), like spread-out fingers radiating from the palm of a hand.
compressed
flattened lengthwise, either laterally (from side to side) or dorsally (from front to back).
concolorous
the same colour throughout, uniformy coloured.
The lobes of the corolla of Nicotiana flowers are conduplicate in the bud.
conduplicate
two sides of a flat surface are folded along the midline to face each other. See also ptyxis, aestivation, and vernation.
cone
a fruit, usually woody, ovoid to globular, including scales, bracts or bracteoles arranged around a central axis, e.g. in gymnosperms, especially conifers and Casuarina.
conflorescence
of an inflorescence when the overall structure substantially differs from that of the individual branches of the inflorescence, a rarely used term; e.g. the bottlebrush multiple-flower head of Callistemons.
connate
fused to another organ (or organs) of the same kind; e.g. petals in a corolla tube; cf. adnate.
connective
the part of an anther that connects the anther cells.
connivent
coming into contact or converging.
conspecific
belonging to the same species.
contiguous
adjoining, touching, but not united.
contort
(sepals and petals) a type of imbricate aestivation in which one side of each segment overlaps one of the adjacent segments and the other side is overlapped by the other adjacent segment. see: convolute
contorted
twisted out of the normal shape.
convolute
1. referring to the arrangement of floral or foliar organs in a bud when each organ or segment has one edge overlapping the adjacent organ or segment; a form of imbricate arrangement; contort.
2.  (leaves) a type of vernation in which one leaf is rolled up inside another.
3.  a type of vernation of two leaves at a node, in which one half of each leaf is exposed and the other half is wrapped inside the other leaf.
cordate
heart-shaped, with the notch lowermost; of the base of a leaf, like the notched part of a heart.
coriaceous
leathery; stiff and tough, but somewhat flexible.
corm
fleshy, swollen stem base, usually underground, storing food reserves, with buds naked or covered by very thin scales; a type of rootstock. Adjectives derived from "corm" include "cormose" and "cormous".
corolla
collective term for the petals of a flower.
The corona of this Passiflora flowers is a ring of purple filaments between the petals and the stamens.
corona

1. in flowering plants, ring of structures that may be united in a tube, arising from the corolla or perianth of a flower and standing between the perianth lobes and the stamens. The trumpet of a daffodil is a corona.
2.  in grasses, a hardened ring of tissue surmounting the lemma in some species.
cortex
On a lichen, the cortex is the "skin", or outer layer of thallus tissue that covers the medulla Fruticose lichens have one cortex encircling the branches, even flattened, leaf-like forms; foliose lichens have different upper and lower cortices; crustose, placodioid and squamulose lichens have an upper cortex but no lower cortex; and leprose lichens lack any cortex.
corticolous
Growing on bark (compare with lignicolous, growing on wood with the bark stripped off.)
corymb
(adjective corymbose) inflorescence with branches arising at different points but reaching about the same height, giving the flower cluster a flat-topped appearance.
costa
(adjective costate) a rib.
costapalmate
a costapalmate leaf has a definite costa (midrib), unlike the typical palmate or fan leaf, but the leaflets are arranged radially like in a palmate leaf.
cotyledon
primary leaf or leaves of an embryo, becoming the seed leaf or leaves.
craspedodromous
pinnate venation in which the secondary veins terminate at the margins, often as teeth.
crateriform
In the shape of a saucer or shallow cup; hemispherical or more shallow .
cremnophyte
a plant adapted to growing on, especially hanging from, cliff faces or crevices. (from Greek kremao to hang, kremnos cliff, overhanging rock or declivity) Compare chasmophyte[2][3]
crenate
with blunt or rounded teeth, scalloped.
crenulate
minutely scalloped.
crisped
finely curled. A term generally applied to the edges of leaves and petals.
cristarque cell
a sclereid which contains a druse and has the lignin deposited excentrically on the cell wall to form a cup shape, or in cross section, a ∪-shape.
crown
see canopy.
cross
to make something interbreed; the act of hybridization.
cruciform
cross-shaped.
crustaceous
hard, thin and brittle.
Crustose lichens on a wall
crustose
forming a closely applied surface layer, forming a crust
cryptogams
ferns, bryophytes, algae and fungi (including lichenized fungi); 'lower plants'; plants producing spores, and without stamens, ovaries or seeds, literally plants whose sexual reproductive organs are not conspicuous cf. phanerogam.
cucullate
from Latin cucullus, a hood. Hood-like or hooded, commonly referring to the shape of leaves or petals. (Example: Pelargonium cucullatum). Similarly derived terms include cuculliform and cuccularis.
culm
in grasses, sedges, rushes, and some other monocotyledons, an aerial stem bearing the inflorescence; strictly, from the base of the plant to the lowest involucral bract (or base of the inflorescence).
cultigen
a plant whose origin or selection is primarily due to intentional human activity.
cultivar
the term cultivar is derived from cultivated variety and denotes an assemblage of cultivated plants clearly distinguished by one or more characters (morphological, physiological, cytological, chemical or other); when reproduced (sexually or asexually), the assemblage retains its distinguishing characters. A cultivar may arise in cultivation or be introduced from the wild. It is a variant of horticultural interest or value. Cultivar names are written with single quotation marks around them e.g. 'Blue Carpet', 'Alba'. All new names established after 1 January 1959, must be in common language (that is, not in Latin) but names established in Latin prior to this date are retained in Latin form.
cultivar epithet
the defining part of a name that denominates a cultivar. Cultivars are designated by fancy (q.v.) epithets appended either to the scientific name or to the common name of the taxon to which they belong; they are not italicized but placed in single quotation marks, for example Rubus nitidoides 'Merton Early'. 'Merton Early' is the cultivar epithet.
cuneate
wedge-shaped; with straight sides converging at base. See Leaf shape.
cupule
a cup-shaped structure composed of coalescent bracts, such as the cup of an acorn.
cupular
shaped like a cupule.
cupulate
bearing cupules.
cupuliform
nearly hemispherical, shaped like a cupola or dome.
cusp
a pointed tip, hence cuspidate.
cuspidate
tipped with a cusp, for instance leaf shape. Also tricuspidate - with three cusps etc.
cuticle
a waterproofing layer covering the epidermis of aerial plant surfaces, composed of the polymers cutin, and/or cutan and waxes.
cutting
a piece of plant, usually an apical tip of shoot structure but may be root or leaf, cut from plant and used for vegetative propagation.
cyathia
plural of cyathium
<dt class="glossary " id="cyathium, plural "cyathia")" style="margin-top: 0.4em;">cyathium
an inflorescence of unisexual flowers surrounded by involucral bracts, esp. the flowers of Euphorbia.
Euphorbia milii is commercially grown for the aesthetic appearance of its brightly colored, bract-like structures called cyathophylls, which sit below the inflorescence.
cyathophyll
The bract-like structure of a Euphorbia on which the involucre sits, usually but not always occurring in twos. They may sometimes be brightly colored and confused with petals.
cylindrical
rod-like and 2-3 times as long as wide, c.f. baculiform.
cyme
(adjective cymose) inflorescence in which the main axis and all lateral branches end in a flower (each lateral may be repeatedly branched).
cypsela
a dry, indehiscent, one-seeded fruit formed from an inferior ovary.

D

deciduous
falling seasonally, for instance bark, leaves, petals; compare persistent.
declinate
curving downwards, and then upwards at the tip. May be qualified, e.g. declinate-ascendant
decompound
divided to more than one level, as in bipinnate leaves for example, in which the leaflets of what otherwise would be a pinnate leaf, are themselves pinnately divided
decorticate
to shed or peel off the outer bark of a tree.
decumbent
with branches growing horizontally on the ground, but turned up at the ends.
decurrent
extending downwards beyond the point of insertion e.g. when the base of a leaf or a fungal gill is prolonged downwards along the stem in a raised line or narrow wing.
decussant
= decussate. The usage decussant is questionable and occurs rarely, probably as an error. The formally correct usage is decussate.
decussate
opposite, with successive pairs borne at right angles to the last; generally applied to the arrangement of leaves.
definite
of a constant number; e.g. twice as many stamens as the petals or sepals (or less), or an inflorescence ending in a flower or an aborted floral bud, typically a cymose inflorescence; cf. indefinite.
deflexed
bent downwards; compare inflexed.
dehiscent
breaking open at maturity to release contents. Refers e.g. to the opening of fruits to release the seeds, of anthers to release the pollen and sporangia to release the spores. Contrast with indehiscent
deltoid
with the shape of the uppercase Greek letter Δ, i.e. like a more or less equilateral triangle. See Leaf shape.
dendroid
tree-like, branching like a tree.
dentate
toothed. See Leaf margin.
denticulate
finely toothed, a diminutive form of dentate.
deserticolous
inhabiting a desert.
determinate
limited, usually in growth.
diaspore
A reproductive part of a plant, adapted for dispersal and for establishing new plants; a disseminule such as a seed, or specialised buds, branches, inflorescences or fruits.
dichasium
a cymose inflorescence with all branches below the terminal flower in regular opposite pairs; compare monochasium.
dichlamydeous
perianth is divided into separate calyx and corolla. Compare to homochlamydeous, in which they are indistinguishable
dichotomous
forking into two equal branches. This may result from an equal division of the growing tip, or may be sympodial, in which the growing tip is aborted and replaced. Typically refers to mode of branch growth, as in Aloe dichotoma, but also to other organs, such as the thorns of various species of Carissa (which morphologically are branches) and thalli or hyphae of various algae and fungi.
dicotyledon
a flowering plant whose embryo has two (rarely more) cotyledons (seed leaves) (common usage: dicot.) compare monocotyledon (common usage: monocot.).
digitate
with segments spreading from a common centre, like the fingers of a hand; see also palmate, palmatisect.
occurring in 2 different forms (in respect to shape and/or size), for example of stamens, fronds, leaves. See also monomorphic (having a single form) and polymorphic (many forms)
dioecious
of vascular plants, when male and female reproductive structures develop on different individuals. cf. monoecious.
dioicous
of bryophyte gametophytes, when male and female reproductive structures develop on different individuals. cf. monoicous.
diploid
with two full sets of chromosomes in the nucleus of a sporophyte cell, that is one set from each of the parental gametes. This is expressed symbolically as 2n, where n = the number of chromosomes in the haploid gametes.
diplostemonous
stamens arranged in two whorls, with the outer whorl alternating with the petals, while the inner whorl is opposite the petals. Compare: obdiplostemonous.
disk (disc)
a plate or ring of structures derived from the receptacle, and occurring between whorls of floral parts. In some groups, especially Sapindales, the nectary is in the form of a prominent disk. In daisies, the central part of the capitulum is a disk, hence flowers borne there are called disk flowers or florets.
discoid
resembling a disc or plate, having both thickness and parallel faces and with a rounded margin. Also used to describe the flower head of Asteraceae where there are no ray florets, but only disc florets.
discolorous
of leaves, with upper and lower surfaces of a different colour.
disjunct
occurring in widely separated geographic areas, distinctly separate; applies to a discontinuous range in which one or more populations are separated from other potentially interbreeding populations far enough as to preclude gene flow between them.
dissected
deeply divided; cut into many segments.
distal
remote from the point of origin or attachment; the free end; cf. proximal.
distichous
arranged in two opposite rows (and hence in the same plane).
distinct
separate or free, not united.
distyly
the condition in which the flowers of a species occur in two forms that differ only by the length of the style and stamens, and flowers of only one of these forms appear on any one plant. see:heterostyly
diurnal
of the day; occurring or opening in the daytime.
divaricate
wide-spreading.
divergent
spreading in different directions, generally upward.
division
the term used for the rank below kingdom in the taxonomic hierarchy.
Leaves of Epipremnum aureum have a drip tip
domatia
(singular domatium) Any hollow structure formed by a plant that is inhabited by animals such as ants or mites.
dorsal
at the rear or back, facing away from the axis (abaxial) in a lateral organ or away from the substrate in a prostrate plant.
dorsifixed
attached at or by the back, e.g. anthers on a filament.
dorsiventral
having structurally different upper and lower surfaces, e.g. some leaves.
drip tip
a long, narrow, caudate or acuminate extension at the tip of a leaf or leaflet.
drupe
a succulent fruit formed from one carpel; the single seed is enclosed by a stony layer of the fruit wall; kernel; e.g. peaches, olives.
drupelet
a drupe, usually small, formed from one of the carpels in an apocarpous flower. Drupelets usually form a compound fruit, as in Rubus, but they may become widely separated, as in Ochna.
druse
a globular mass of calcium oxalate crystals, usually with the crystals radiating from an organic core.

E

-eae
The suffix added to the stem of a generic name to form the name of a tribe: for instance, AsterAstereae.
ebracteate
without bracts. Similarly ebracteolate.
ecological amplitude
the range of environmental conditions in which an organism can survive.
edaphic
Influenced by or of the soil.
elaiosome
oily body attached to the seed.
elephophily
a form of pollination whereby pollen or spores are distributed by the feet of elephants, as in Rafflesia arnoldii
ellipsoid
a 3-dimensional shape, elliptical in all sections through the long-axis.
elliptical (elliptic)
planar, shaped like a flattened circle, symmetrical about both the long and the short axis, tapering equally both to the tip and the base; oval.
emarginate
notched at apex (notch usually broad and shallow).
embryo
young plant contained by a seed.
emergent
a plant taller than the surrounding vegetation or, for a water-based plant, one whose leaves and flowers are above the water.
enantiostyly
the condition in which the gynoecium protrudes laterally, to the right (dextrostyly) or to the left (sinistrostyly) of the androecium. example: Senna.
endemic
having a natural distribution restricted to a particular geographic region; cf. native.
endocarp
the innermost layer of the wall of a fruit; in a drupe, the stony layer surrounding the seed.
endodermis
the innermost layer of the cortex of vascular plant roots, also present in the stems of pteridophytes. The radial walls are impregnated with suberin to form a permeability barrier known as the Casparian strip.
endophloeodal
endophloic
endophloic
(synonym – endophloeodal) of crustose lichens, having the thallus growing within rather than on the bark of trees,[4]:159 Compare with epiphloedal or corticolous growing on the surface wood or bark; also cf. endolithic growing within rock, not wood
endosperm
1.  (angiosperms) a nutritive tissue surrounding the embryo of the seed, usually triploid, originating from the fusion of both polar nuclei with one gamete after the fertilization of the egg.
2.  (gymnosperms) the prothallium within the embryo sac.
ensiform
shaped like the blade of a sword.
entire
1.  not divided.
2.  (of a margin) having a smooth margin, not lobed or toothed (it may be wavy or scalloped).
entomophily
a form of pollination whereby pollen or spores are distributed by insects.
ephemeral
short-lived. See also caducous.
The enlarged calyx and smaller epicalyx of Hibiscus sabdariffa
epicalyx
an involucre resembling an outer calyx; e.g. as seen in Hibiscus.
epicarp
the outer layer of the wall of a fruit, i.e. the 'skin'.
epicormic
said of buds shoots or flowers developing from the old wood of trees, especially after injury or fire.
epicotyl
the part of the plant axis or stem between the cotyledonary node and first foliage leaves.
epicuticular wax
a layer of crystalline or amorphous wax deposited on the surface of the plant cuticle.
epidermis
an organ's outermost layer of cells, usually only one cell thick.
epigynous
borne on the ovary; describes floral parts when attached above the level of the ovary and arising from tissue fused to the ovary wall; cf. hypogynous, perigynous.
An epilithic lichen
epilithic
growing on stone; compare lithophytic, a plant growing on stone.
epinecral
Dead tissue (necral) above the surface of the cortex of a lichen.
epipetalous
of stamens that are attached to the petals.
epiphloedal
Growing on bark; cf. endophloedal - growing inside, not on, the bark; cf. epilithic - growing on rock, not bark.
epiphytic
Living on the surface of a plant; cf. lithophytic.
epitepalous
of stamens that are attached to the tepals.
epiphyte
(adjective epiphytic) one plant growing on another without deriving nourishment from it (in other words, not parasitic); compare parasite. Loosely, and incorrectly, applied to plants that are not terrestrial (they may grown on various inorganic or organic surfaces), and often to orchids, which are rock-dwelling (and therefore strictly lithophytic).
epithet
the adjectival component in a binomial; final word or combination of words in a name of more than one word (other than a term denoting rank) that denominates an individual taxon.
Seeds or fruit are dispersed by epizoochory when they stick to the fur of animals.
epizoochory
Seed dispersal by sticking on the outside of vertebrate animals.
epruinose
not pruinose
The bases of equitant leaves enclose later leaves on the stem.
equitant
of a leaf when folded lengthwise and clasping another leaf.
erect
upright, more or less perpendicular to the ground or point of attachment. Compare patent (spreading). Erecto-patent, between erect and patent.
ericoid
with leaves like those of the European heaths (Erica), small and sharply pointed.
erose
with the margin irregular as though nibbled or worn away.
even-pinnate
having an even number of leaflets in a compound leaf, = paripinnate.
evergreen
not deciduous, having leaves all the year round.
ex
in nomenclature, indicating that the preceding author proposed the name but did not legitimately publish it, and that the succeeding author referred to the first author when legitimately publishing the name. See Author citation (botany).
exocarp
the outer layer of the pericarp, often the skin of fleshy fruits.
exotesta
the outer layer of the testa (seed coat). It is derived from the outer integument of the ovule.
exotic
not native; introduced from another region or country.
exserted
projected beyond, e.g. the stamens beyond the corolla tube.
exstipulate
without stipules.
extrastaminal
outside the stamens or androecium, usually referring to the location of a nectary disk.
extrorse
of anther locules, opening towards the outside of the flower; cf. introrse, latrorse.

F

F1 hybrid
a single cross; a plant breeding term for the result of a repeatable cross between two pure bred lines.
F2 hybrid
a plant breeding term for the result of a plant arising from a cross between two F1 hybrids; may also refer to self-pollination in a population of F1 hybrids.
fabiform
shaped like a kidney-bean.
facultative
of parasites, optional; compare obligate.
falcate
curved like the blade of a scythe.
family
a formal group of one or more genera with features and/or ancestry in common; the term for the principal rank between order and genus.
farinaceous
powderiness that is mealy
fascicle
(adjective fasciculate) cluster, e.g. a tuft of leaves all arising from the same node.
fasciculate
branching in a cluster like a bundle of sticks or needles, having fascicles.
faveolate
honeycombed. With regular, angled pits. Compare foveolate.
faucal
pertaining to the fauces; located in the throat of a calyx or corolla.
fauces
the throat of a calyx or corolla; the conspicuously widened portion between the mouth and the apex of the tube. In Boraginaceae, the site of distinctive appendages.
felted
covered with very dense, interlocked and matted hairs with the appearance or texture of felt or woollen cloth.
The leaves of Darlingtonia californica are fenestrate.
fenestrate
with translucent areas. See also perforate, with holes.
ferruginous
rust-colored.
fertile
capable of producing fruit; of flowers when they produce seed or of anthers containing pollen.
fertilization
union of male and female gametes.
fiber
1.  a fiber cell.
2.  any flexible, strong, stringy, and very elongate structure.
fiber cell
a type of cell that is found in sclerenchyma, it is much elongated and dies soon after an extensive modification of its cell wall. The cell wall is usually thickly lignified, but is sometimes gelatinous.
filament
1.  stalk of a stamen
2.  thread, one or a few cells thick.
filamentous
consisting of filaments or fibres, hairlike.
filiform
thread-like. e.g. stamen filaments, or leaf shapes.
fimbria
slender hair-like process (plural: fimbriae)
fimbriate
fringed.
fissure
a split or crack, often referring to fissured bark. also, a line or opening of dehiscence.
fistule
A tube-shaped cavity.
fistulose
Hollow, usually applied to a tube-shaped cavity as in a reed.
flabellate
fan-shaped.
flaccid
limp; tending to wilt; compare turgid.
flexuous (flexuose)
bent alternately in different directions; zig-zag.
floccose
with a soft and woolly covering of hairs.
flora
1.  all the plants growing in a certain region or country.
2.  an enumeration of them, generally with a guide to their identification (e.g. the present volume, the Flora of Victoria, the Flora of New South Wales and so on). In this case 'flora' is written with a capital F.
floral envelope
See perianth.
floral leaves
the upper leaves at the base of the flowering branches.
floral diagram
graphical means to describe the flower structure, a schematic cross-section through a young flower.
floral formula
textual means to describe the flower structure using numbers, letters and various symbols.
floral tube
an imprecise term sometimes used as a synonym of hypanthium or of corolla tube or of calyx tube.
floret
literally a small flower, but usually refers to the individual true flowers clustered within an inflorescence, particularly in inflorescences of the daisy and grass families.
flower
the sexual reproductive structure of the Angiosperms, typically with a gynoecium, androecium, perianth and an axis.
foliate
preceded by a number: having a certain number of leaflets; for example, 3-foliate, "having three leaflets"
foliicolous
growth habit of certain lichens, algae, and fungi that prefer to grow on the leaves of vascular plants.
follicle
a dry fruit formed from one carpel, splitting along a single suture, to which the seeds are attached; cf. pod (of legume).
foliole
a small leaf-like appendage on the front or back.
The foliose thallus of the lichen, Parmotrema tinctorum, is leafy.
foliose
leaflike, flattened like a leaf
forb
any non-woody flowering plant that is not a grass, sedge, or rush.
forest
vegetation dominated by trees with single trunks (including closely arranged trees with or without an understorey of shrubs and herbs).
forma (in common usage, form)
a taxonomic category subordinate to species and within the taxonomic hierarchy, below variety (varietas), usually differentiated by a minor character.
foveolate
with regular tiny pits. Compare faveolate.
free
not united with others organs of the same type; not attached at one end.
free central
of placentation, ovules attached to a free-standing column in the centre of a unilocular ovary.
frond
a leaf of a fern, cycad or palm.
frutescent
shrub-like (fruticose) or becoming shrub-like
Letharia vulpina is a fruticose lichen
fruticose
shrubby, with the branching character of a shrub
fruit
seed-bearing structure in angiosperms formed from the ovary, and sometimes associated floral parts, after flowering.
fugacious
disappearing, falling off, or withering; compare persistent and caducous.
funicle (funiculus)
the stalk of an ovule.
funnelform
with a form gradually widening from the base to apex; funnel-shaped.
furcate
forked, usually applied to a terminal division; with two long lobes.
fused
joined together.
fusiform
rod-shaped and narrowing gradually from the middle towards each end; spindle-shaped.

G

galbulus
(in gymnosperms) a fleshy cone (megastrobilus); chiefly relates to those borne by junipers and cypresses and often mistakenly called berries.
gamete
a cell or nucleus that fuses with another of the opposite sex in sexual reproduction.
gametophyte
the haploid multicellular phase in the alternation of generations of plants and algae that bears gametes. In bryophytes the gametophyte is the dominant vegetative phase; in ferns and their allies it is a small free-living plant known as the prothallus; in gymnosperms and angiosperms the gametophytes are reduced to microscopic structures dependent on the sporophyte, male gametophytes contained in pollen grains and females contained within the ovules.
gene pool
the range of genetic variation found in a population.
genus
(plural genera) a group of one or more species with features or ancestry (or both) in common. Genus is the principal category of taxa intermediate in rank between family and species in the nomenclatural hierarchy.
generic name
the name of a genus, for example Acacia, Eucalyptus.
genotype
the genetic make-up of an individual.
germination
1.  of seeds, describing the complex sequence of physiological and structural changes that occur from resting to growth stage.
2.  of a pollen grain; production of a pollen tube when contacting a stigma receptive to it.
3.  of a spore of fungi/bacterium; change of state – from resting to vegetative.
gibbous (gibbose)
when part of an organ is swollen; usually with a pouch-like enlargement at base.
glabrescent
becoming glabrous, almost glabrous.
glabrous
without surface ornamentation such as hairs, scales or bristles; (in lichenology) having no indumentum.
gland
a secretory structure within or on the surface of a plant.
glandular hair
hairs tipped with a gland.
glaucous
with a whitish bloom, blue-green in colour; e.g. the surface of the young leaves of many eucalypts.
globose (globular)
spherical. See also subglobose.
globulose
approximately spherical.
glochid
a barbed hair or bristle, e.g. the fine hairs in Opuntia.
glumes
bracts subtending the floret(s) of a sedge, or similar plant; in grasses forming the lowermost organs of a spikelet (there are usually 2 but 1 is sometimes reduced; or rarely, both are absent).
glutinous
sticky.
graft
1.  of a plant, the artificial union of plant parts.
2.  a plant shoot suitable for grafting; loosely means a scion, #sucker or branch.
graft chimaera (sometimes graft hybrid)
a taxon whose members consist of tissue from two or more different plants in intimate association originated by grafting. The addition sign "+" is used to indicate a graft-chimaera either as a part of a formula (e.g. Crataegus monogyna + Mespilus germanica), or in front of an abbreviated name (e.g. +Crataegomespilus 'Dardari'). The nomenclature of graft hybrids is governed by the International Code of Nomenclature for Cultivated Plants.
granular
of a surface, covered with small rounded protuberances.
grass
a plant belonging to the family Poaceae.
grassland
low vegetation dominated by grasses.
groundcover
1.  of dense vegetation that covers the ground.
2.  a term applied to describe a plant that covers the soil surface so densely that it smothers all beneath it.
Group

a formal category equivalent to or below the rank of genus. It distinguishes:

1. an assemblage of two or more cultivars within a species or hybrid.
2.  plants derived from a hybrid in which one or more of the parent species is not known or is of uncertain origin.
3.  a range of cultivated plants of a species or hybrid which may exhibit variation but share one or more characters, which makes it worth distinguishing them as a unit.
guard cell
each of the two cells that surround the stoma and control gas exchange between the apoplast of the plant and the external air.
guttate, guttatus
with droplet-shaped spots. Compare punctate, maculate.
guttation
the secretion of liquid water from uninjured plant parts. See hydathode.
guttulate
with or appearing to be spotted with oil droplets; (of spores) having oil droplets inside
gymnosperm
a seed-bearing plant with unenclosed ovules borne on the surface of a sporophyll; includes, among others, conifers, Ginkgo, Gnetum and cycads. From gymno = naked, exposed; compare angio = covered, enclosed.
gynobasic
of a style, arising near the base of the gynoecium, e.g. between the lobes of the ovary.
gynodioecious
of a species, with some plants bearing only bisexual flowers and others bearing only female flowers.
gynomonoecious
of a species, with bisexual flowers and female flowers on the same plant.
gynoecium
female parts of flower; the collective term for the carpels of a flower whether united or free; cf. pistil; androecium. Abbreviation: G. For instance G indicating superior ovary. G(5) indicates having 5 fused carpels.
gynophore
stalk supporting the gynoecium (above the level of insertion of the other floral parts).

H

habit
the general external appearance of a plant, including size, shape, texture and orientation.
habitat
the place where a plant lives; the environmental conditions of its home.
hafter
a flat attachment that forms when the thallus of a fruticose or foliose lichens comes in contact with a substrate, different from rhizines and hapters.
hair
a single elongated cell or row of cells borne on the surface of an organ.
half-inferior
of ovary, partly below and partly above the level of attachment of the other floral parts; compare inferior, superior.
halonate
having a transparent coating, or being of a spores outer layer.
halophyte
a plant adapted to living in highly saline habitats; a plant that accumulates high concentrations of salt in its tissues.
hand-pollination
the controlled act of pollination that excludes the possibility of open-pollination.
haploid
with one set of chromosomes, e.g. the complement of chromosomes in each of the cells of the gametophyte, the nucleus of a gamete and the spores. This is expressed symbolically as n, where n = the gamete number of chromosomes.
hapter
an attachment that may form when a foliose lichen thallus comes in contact with a substrate.
hastate
triangular in outline, the basal lobes pointing outwards, so that the base appears truncate; may refer only to the base of a leaf with such lobes; cf. sagittate which refers to basal lobes pointing backwards.
haustorium
in parasitic plants, a structure developed for penetrating the host's tissues.
see capitulum, a pseudanthium.
heathland
vegetation dominated by small shrubs which usually have ericoid leaves.
helicoid
coiled; of a cymose inflorescence, when the branching is repeatedly on the same side (the apex is often recurved); cf. scorpioid.
herb
a vascular plant that does not develop a woody stem; e.g. a violet.
herbaceous
not woody; usually green, and soft in texture.
herbarium
a collection of preserved, usually dried, plant material. Also a building in which such collections are stored.
hermaphrodite
Synonym of bisexual.
heteroblastic
having parts, especially leaves, that are distinctly different between the juvenile and adult stages.
heteromorphic
of 2 or more distinct morphologies (e.g. of different size and shape).
heterostyly
the condition of a species having flowers with different style and stamen lengths, but with all the flowers of any one plant being identical. see:distyly
hilum
the scar on a seed coat where it separates from its stalk (funicle).
hip
the fruit of a rose.
hippocrepiform
horseshoe-shaped.
hirsute
bearing coarse, rough, longish hairs. See Indumentum.
hispid
having long erect rigid hairs or bristles, harsh to touch.
hoary
covered with a greyish to whitish layer of very short, closely interwoven hairs, giving a frosted appearance.
holotype
a type chosen by the author of a name; cf. a lectotype, which is chosen by a later author.
homochlamydeous
perianth not divided into calyx and corolla. Compare to dichlamydeous, in which they are separate
hort.

as a name misapplied by gardeners
2.  as an invalid name derived from horticultural writings of confused authorship.
A hypocarpium forms below the fruits of Sassafras albidum
hyaline
translucent; usually delicately membranous and colourless.
hybrid
a plant produced by the crossing of parents belonging to two different named groups, e.g. genera, species, varieties, subspecies, forma and so on; i.e. the progeny resulting within and between two different plants. An F1 hybrid is the primary product of such a cross. An F2 hybrid is a plant arising from a cross between two F1 hybrids (or from the self-pollination of an F1 hybrid).
hybrid formula
the names of the parents of a hybrid joined by a multiplication sign, e.g. Cytisus ardonoi × C. purgans.
Hydrophily
a form of pollination whereby pollen is distributed by the flow of waters.
hypanthium
A tube or cup-like structure in a flower that includes the bases of sepals, petals, and stamens, and may or may not be connected (adnate) to the ovary.
hyper-resupinate
1.  In botany, describing leaves or flowers that are in the usual position, but are borne on a petiole or pedicel, respectively, that is twisted 360 degrees. The term is used to describe organs, such as orchid flowers, that are usually resupinate. compare: #resupinate
hypocarpium
an enlarged fleshy structure that forms below the fruit, from the receptacle or hypanthium.
hypocotyl
of an embryo or seedling, the part of the plant axis below the cotyledon and node, but above the root. It marks the transition from root to stem development.
hypocrateriform
salverform.
hypogynous
borne below the ovary; used to describe floral parts inserted below the ovary's level of insertion; cf. epigynous, perigynous.
hypothallus
The hypothallus is the outgrowth of hyphae from under the margin of the thallus of a crustose lichens, connecting the island-like areoles into a single lichen.
hysteranthous (histeranthous)
new leaves appear after flowering. See also proteranthous and synanthous

I

idioblast
a cell, especially of a leaf, differing markedly from surrounding cells. They often synthesise specialised products such as crystals.
illegitimate name (nomen illeg.)
a name not abiding by the rules of the botanical Codes, e.g. later homonyms, cultivars that have been Latinised after 1 Jan 1959; cultivar names with more than 10 syllables or 30 letters; cultivar names that use confusing names of other plants, e.g. Camellia 'Rose'.
imbricate
overlapping each other; of perianth parts, edges overlapping in the bud (the convoluted arrangement is a special form of imbrication).
imparipinnate
a pinnate leaf with an odd number of pinnae (terminated by a single leaflet); compare paripinnate.
in
in nomenclature, where the preceding author published the name in an article or book, authored or edited by the succeeding author.
-inae
The suffix added to the stem of a generic name to form the name of a subtribe: for instance, Corydalinae from Corydalis + -inae.
inbreeding
the production of offspring between closely related parents leading to a high degree of similarity; self-fertilization is the most intense form of inbreeding.
incertae sedis
of unknown taxonomic affinity, relationships obscure.
incised
cut deeply and (usually) unevenly (a condition intermediate between toothed and lobed).
included
enclosed, not protruding; for example stamens within the corolla.
incurved
bent or curved inwards; of leaf margins, when curved towards the adaxial side.
ined.
abbreviation of Latin inedita, an unpublished work. Used to indicate that a botanical name appeared only in a manuscript that was not published, so the name is invalid.
indefinite
variable in number; numerous; e.g. more than twice as many stamens as petals or sepals, or when an inflorescence is not terminated by a flower (and continues growing); cf. definite.
indehiscent
not opening in any definite manner at maturity; usually referring to fruit. Contrast with dehiscent.
indeterminate
unlimited, usually in growth.
indigenous
native to the area, not introduced, and not necessarily confined to the region discussed or present throughout it (hardly distinct from ‘native’ but usually applied to a smaller area). For example, the Cootamundra Wattle is native to Australia but indigenous to the Cootamundra region of southern New South Wales; cf. endemic.
indumentum
a collective term for a surface covering of any kind of trichomes, e.g. hairs, scales.
The leaves of Syagrus palms are induplicately folded, in contrast to many other palm genera with reduplicate leaves.
induplicate
folded upwards, or folded with the two adaxial surfaces together.
indusium
1.  a membrane covering the sporangia of some ferns.
2.  a cup enclosing the stigma in Goodeniaceae.
inferior
of an ovary, at least partly below the level of attachment of other floral parts; compare superior.
inflated
swollen, like a bladder.
inflexed
bent sharply upwards or forwards; compare deflexed.
inflorescence
several flowers closely grouped together to form an efficient structured unit; the grouping or arrangement of flowers on a plant.
infraspecific
denotes taxonomic ranks below species level, for example subspecies.
infrageneric
denoting taxonomic ranks below the genus level, for example, subgenera, sections, and series.
infructescence
the grouping or arrangement of fruits on a plant.
wikt:infundibular (infundibuliform)
funnel-shaped, for example in the corolla of a flower.
inrolled
rolled inwards.
insectivorous
catching, and drawing nutriment from, insects.
insertion, point of
the point at which one organ or structure (such as a leaf) is joined to the structure which bears it (such as a stem).
Stamens of Calotropis gigantea are inserted at the base of the corolla.
inserted
growing out from
integument
in general, any covering, but especially the covering of an ovule.
intercalary
(e.g. of growth) occurring between the apex and the base of an organ
intercalary meristem
a meristem located between the apex and the base of an organ
interjugary glands
in pinnate leaves, glands occurring along the leaf rachis between the pinnae (occurring below the single, and often slightly larger, gland at or just below the insertion of the pinnae); cf. jugary.
internode
the portion of a stem between two nodes.
interpetiolar
of stipules, between the petioles of opposite leaves, e.g in Rubiaceae.
intramarginal
inside but close to the margin, for example a vein in a leaf.
intrastaminal
inside the stamens or androecium, usually referring to the location of a nectary disk.
introrse
of anther locules, with opening towards the centre of flower (at least in bud); cf. extrorse, latrorse.
invalid
use of names not validly published according to the Code; i.e. they are not strictly 'names' in the sense of the International Code of Botanical Nomenclature.
Two of these three green Asteraceae involucres encase unopened flower heads, and the third support the open colorful head of emerging flowers. The rows of phyllaries in this, of Snake's head appear like keeled scales of a snake, giving the plant its common name.
involucre
A structure surrounding or supporting, usually a head of flowers. In Asteraceae, it is the group of phyllaries (bracts) surrounding the inflorescence before opening, then supporting the cup-like receptacle on which the head of flowers sits. In Euphorbiaceae it is the cuplike structure that holds the nectar glands, nectar, and head of flowers, and sits above the bract-like cyathophyll structure. Involucres occur in Marchantiophyta, Cycads, fungi, and many other groups.
involute
rolled inwards, for example when the margins of a leaf are rolled towards the adaxial (usually upper) surface; compare revolute.
iridescent
with a reflective coloured sheen produced by structural coloration, as in the speculum of the mirror orchid Ophrys speculum.
irregular
cannot be divided into two equal halves through any vertical plane. See also asymmetrical, compare zygomorphic, actinomorphic, regular.
isidium
A warty of club-like structure in some lichens that breaks off and forms new lichens without sexual reproduction. Isidia are dispersed by mechanical means, compared to soredia, which are dispersed by wind.
isobifacial
(of flat structures, especially leaves) with both surfaces similar, usually referring to cell types or to the number and distribution of stomata.
isomerous
Having an equal number of parts in the whorls.
isotomic
having branches of equal diameter, compare to anisotomic.

J

joint
a node or junction of two parts; articulation.
jugary
of glands, gland occurring on the rachis of a bipinnate leaf at the junction or attachment of pairs of pinnae or pinnules, as in some Acacia species; cf. interjugary.
juvenile leaves
formed on a young plant and different in form from the adult leaves.

K

K, K+, K-
In lichenology, "K" is the abbreviation for the outcome of a test in which a 10% solution of potassium hydroxide (KOH — hence "K") is placed on lichen tissues. Color change is noted by "K-" for none, and K+ for a yellow to red or purple color.
keel
(adj. keeled), a prominent longitudinal ridge like the keel of a boat, e.g. the structure of the corolla formed by the fusion of the lower edge of the two abaxial anterior petals of a flower in the Fabaceae.
kernel
see drupe.
key innovation
a novel phenotypic trait that allows subsequent evolutionary radiation and success of a taxonomic group.
kingdom
the highest generally employed category of the taxonomic hierarchy, above that of division (phylum). The Plant Kingdom includes vascular plants, bryophytes and green algae and is also known as the clade Viridiplantae.

L

labellum
lip; one of three or five petals which is (usually) different from the others, e.g. in Orchidaceae and Stylidiaceae.
labiate
lipped; where a corolla is divided into two parts, called an upper and lower lip, the two resembling an open mouth with lips.
lacerate
jagged, as if torn.
lacinia
In foliose lichens, a linear to elongate lobe, usually arising from or at the end of a larger lobe
laciniate
Of lobes - with ends irregularly divided into deeply divided, narrow, pointed segments; Of margins - deeply divided into pointed segments in an irregular manner.
lacuna
An empty space, hole, cavity, pit, depression, or discontinuity.
lamella
a thin, plate-like layer. (plural lamellae; adjective lamellate - composed of an assemblage of many layers)
lamina
the blade of a leaf or the expanded upper part of a petal, sepal or bract.
laminal
of, or pertaining to, the upper surface, such as the cortex of a lichen.
lanceolate
longer than broad, narrowly ovate, broadest in the lower half and tapering to the tip, like a lance or spear head; (sometimes, and incorrectly, used to mean narrowly elliptic).
lateral
attached to the side of an organ, e.g. leaves on a stem.
latex
a milky fluid that exudes from such plants such as spurges, figs and dandelions.
laticiferous
latex-bearing, producing a milky juice.
latrorse
a type of anther dehiscence in which the anthers open laterally toward adjacent anthers. cf. introrse, extrorse.
lauroid
resembling Laurus, the laurel genus, particularly its leaves.
lax
loose, not compact. Of bundles of hyphae in lichens - not stiff and not adglutinate.
leaf
an outgrowth of a stem, usually flat and green; its main function is food manufacture by photosynthesis. Abbreviation: lvs.
leaf gap
a parenchymatous area in the stele above (distal to) a leaf trace.
leaf scar
a healing layer forming on the stem where the leaf has fallen off.
leaf trace
a vascular bundle connecting the stele to a leaf.
leaflets
the ultimate segments of a compound leaf.
These lecanorine apothecia of the lichen Lecanora muralis have scrunched rims of tissue similar to the tissue of the main thallus body.
lecanorine
of lichens, having apothecia with rims of tissue similar to the tissue of the thallus, as in the genus Lecanora[5]
legume
1.  a fruit characteristic of the family Fabaceae, formed from one carpel and either dehiscent along both sides, or indehiscent.
2.  a crop species in the family Fabaceae.
3.  a plant belonging to the Fabaceae family).
lemma
the lower of 2 bracts enclosing a grass flower.
The dark horizontal lines on Silver birch bark are lenticels
lenticel
Typically lens-shaped (lenticular) porous tissue in bark with large intercellular spaces that allows direct exchange of gases between the internal tissues and atmosphere through the bark.
lenticular
1.  lens-shaped.
2.  covered in lenticels
lepidote
covered with small scales.
leprose
powdery
liana
a woody climbing plant, rooted in the ground (liane is also used).
liane
a woody climbing plant, rooted in the ground. See also liana.
lichenicolous
growing on or in lichens, often but not necessarily as parasites
ligneous
woody
lignum
Dead wood, typically in the context of a substrate for lichens.
lignicolous
Growing on wood tissue after bark as fallen or been stripped off (compare to corticolous)
lignotuber
a woody swelling of the stem below or just above the ground; contains adventitious buds from which new shoots can develop, e.g. after fire.
ligulate
1.  bearing a ligule.
2.  strap-shaped.
ligule
1.  small membranous appendage on the top of the sheath of grass leaves.
2.  a minute adaxial appendage near the base of a leaf, e.g. in Selaginella.
3.  extended, strap-like corolla of some daisy florets.
linea, line, British line, Paris line
various pre-metric units somewhat larger than 2 mm, used in botany into the 20th century. See Line (unit) and Paris line.
linear
very narrow in relation to its length, with the sides mostly parallel. See Leaf shape.
lithophytic
a plant growing on rocks; an epilithic plant.
lobe
part of a leaf (or other organ), often rounded, formed by incisions to about halfway to the midrib.
loculicidal
of a fruit, when it dehisces through the centres of loculi; cf. septicidal.
locule
a chamber or cavity containing seeds within an ovary, pollen within an anther or spores in a sporangium.
lodicule
one of 2 or three minute organs at the base of the ovary of a grass flower, representing parts of a strongly reduced perianth.
lomentum
a pod-like indehiscent fruit that develops constrictions between the segments and at maturity breaks into one-seeded segments.
longicidal
(anthers) opening lengthwise by longitudinal slits. compare: poricidal
lunate
crescent-shaped.
lyrate
lyre-shaped; deeply lobed, with a large terminal lobe and smaller lateral ones.

M

maculate
spotted, marked with spots.
Malesia
a biogeographic region comprising Malaysia, Indonesia, New Guinea, and the Philippines.
mallee
growth habit in which several woody stems arise separately from a lignotuber; a plant with such a growth habit, e.g. many Eucalyptus species; vegetation characterized by such plants.
mangrove
a shrub or small tree growing in salt or brackish water, usually characterized by pneumatophores. Tropical coastal vegetation characterized by such species.
margin
the edge, as in the edge of a leaf blade.
marginal
occurring at or very close to the margin.
marsh
a waterlogged area; swamp.
mast
edible fruit and nuts produced by woody species of plants, i.e. acorns and beechmast, that wildlife species and some domestic animals consume.
mealy
covered with coarse, floury powder.
medulla
1.  In a lichen, the typically undifferentiated tissue underneath the cortex of the thallus, or between the upper and lower cortex if both are present. The medulla is analogous to the tissues underneath the epidermis (skin) of a leaf. The uppermost region commonly contains most of the photobionts.
2.  pith. See also medullary rays in wood.
megaspore
the larger of two kinds of spores produced by a heterosporous plant giving rise to the female gametophyte; compare microspore.
megastrobilus
the larger of two kinds of cones or strobili produced by gymnosperms, being female and producing the seeds; compare microstrobilus.
membranous
thin, translucent and flexible, seldom green.
mericarp
one segment of a fruit (a schizocarp) that splits at maturity into units derived from the individual carpels, or a carpel, usually 1-seeded, released by the break-up at maturity of a fruit formed from 2 or more joined carpels.
meristem
an actively dividing tissue.
mesic
moist, avoiding both extremes of drought and wet; pertaining to conditions of moderate moisture or water supply; applied to organisms (vegetation) occupying moist habitats.
mesocarp
the fleshy portion of the wall of a succulent fruit inside the skin and outside the stony layer (if any), surrounding the seed(s); sarcocarp.
mesomorphic
soft and with little fibrous tissue, but not succulent.
mesophyll
1.  mesophyll tissue, photosynthetic tissue of a leaf, the central tissues between the upper and lower epidermis.
2.  in ecology, the blade of a leaf or leaflet that has a surface area 4500–18225 mm2; A plant, or vegetation, that has mesophyll (sized) leaves.
mesophyllous
(of vegetation) of moist habitats and having mostly large and soft leaves.
mesophyte
a plant thriving under intermediate environmental conditions of moderate moisture and temperature, without major seasonal fluctuations.
microspore
the smaller of two kinds of spores produced by a heterosporous plant; compare megaspore.
microstrobilus
the smaller of two kinds of cones or strobili produced by gymnosperms, being male and producing the pollen; compare megastrobilus.
midrib
the central, and usually most prominent, vein of a leaf or leaf-like organ; midvein.
midvein
see midrib.
monad
a single individual that is free from other individuals, not united with them into a group. The term is usually used for pollen to distinguish single grains from tetrads or polyads.
moniliform
resembling a string of beads.
monocarpic
flowering and setting seed only once before dying. See also semelparous, semelparity
monochasium
a cymose inflorescence with the branches arising singly; cf. dichasium.
monocots
abbreviation of monocotyledons.
monocotyledon
a flowering plant whose embryo has one cotyledon (seed leaf); compare dicotyledon.
monoecious
of vascular plants, hermaphrodite, with all flowers bisexual; or with male and female reproductive structures in separate flowers but on the same plant; or of an inflorescence that has unisexual flowers of both sexes; cf. dioecious.
monoicous
of bryophyte gametophytes, hermaphrodite, bisexual, when both male and female reproductive structures develop on the same individual. cf. dioicous.
monograph
of a group of plants, a comprehensive treatise presenting an analysis and synthesis of taxonomic knowledge of that taxon; the fullest account possible (at the time) of a family, tribe or genus. It is generally worldwide in scope and evaluates all taxonomic treatments of that taxon including studies of its evolutionary relationships with other related taxa, and cytological, genetic, morphological, palaeobotanical and ecological studies. The term is often incorrectly applied to any systematic work devoted to a single taxon. Compare revision.
monomorphic
of one type, rather than several. See also dimorphic (two types) and polymorphic (many types)
monophyllous
Having a single leaf.
monopodial
a mode of stem growth and branching in which the main axis is formed by a single dominant meristem.
monostromatic
Being a single cell thick, as in the alga Monostroma.
monotypic
containing only one taxon of the next lower rank, e.g. a family with only one genus, or a genus that includes only a single species.
morphology
the shape or form of an organism or part thereof.
mucro
Diminutive: mucronule. A sharp, short point, generally at the tip of a leaf or the tip of the midrib of a compound leaf.[2]
mucronate
terminating in a mucro.
multiple fruit
a cluster of fruits produced from more than one flower and appearing as a single fruit, often on a swollen axis, as in Moraceae; cf. aggregate fruit.
muricate
covered with short hard protuberances.
mutation
an abrupt and inexplicable variation from the norm, such as the doubleness in flowers, changes in colour, or habit of growth.
mycobiont
The fungal component of a lichen (compare to photobiont.
mycelium
The "vegetative" (nonreproductive) part of a fungus, mostly composed of aggregations of hyphae. It functions in substrate decomposition and absorption of nutrients.
mycobiont
The fungal component of a lichen (compare to photobiont.
mycorrhiza
one of several types of symbiotic association between a fungus and the roots of a plant.
mycotroph
a plant that obtains most or all of its carbon, water and nutrients by associating with a fungus.

N

native
naturally occurring in an area, but not necessarily confined to it; cf. endemic.
natural hybrid
a hybrid taxon produced by chance in the wild.
naturalised
describing a plant, introduced from another region, that grows and reproduces readily in competition with the natural flora.
nectar
a (usually sweet) fluid produced by the flowers of many plants, collected by bees and other insects.
nectary
(adjective nectariferous) a specialized gland that secretes nectar.
neophyte
a plant that was recently introduced to a geographic area; cf. archaeophyte.
nerve
synonym of vein.
node
the part of a stem where leaves or branches arise.
nomen conservandum
(Latin) a conserved name, usually a name that became so much better known than the correct name, that a substitution was made.
nomen illegitimum
(Latin), a name that is either superfluous at its time of publication because the taxon to which it was applied already has a name, or the name has already been applied to another plant (a homonym).
nomen invalidum
(Latin, see valid publication) a name that is not validly published, and technically is therefore not a botanical name. (Abbreviation: nom. inval.)
nomen nudum
(Latin) a name not published in accordance with the International Code of Nomenclature for algae, fungi, and plants, usually without a diagnosis or description of the entity to which it applies, and without reference to either; such a name should not be used.
nomenclature
the naming of things; often restricted to the correct use of scientific names in taxonomy; a system that sets out provisions for the formation and use of names.
noxious
of plants, containing harmful or unwholesome qualities. Applied in conjunction with 'weed' to specifically describe a plant which legislation deems harmful to the environment. Each state and territory in Australia has specific legislation governing noxious weeds.
nucellus
the tissue of the ovule of a seed plant that surrounds the female gametophyte. It is enclosed by integuments and is not of epidermal origin.
numerous
Stamens are described as numerous when there are more than twice as many as sepals or petals, especially when there is no set number of them.
nut
a hard, dry, indehiscent fruit, containing only one seed.
nutlet
a small nut, one of the lobes or sections of the mature ovary of some members of the Boraginaceae, Verbenaceae, and Lamiaceae.

O

ob-
inversely; usually same shape as suffix but attached by the narrower end, for example obcordate, oblanceolate, obovate.
obconic
of a fruit, hypanthium, pistil or calyx structure; an inverted cone shape, attached at apex.
obcordate
of a leaf blade, broad and notched at the tip; heart shaped but attached at the pointed end.
obdiplostemonous
stamens arranged in two whorls, and having twice as many as the petals, the outer whorl being opposite the petals. Compare: diplostemonous.
oblanceolate
a 2-dimensional shape, lanceolate but broadest in the upper third.
obligate
of parasites, unable to survive without the host; compare faculative.
oblique
slanting; of a leaf or stem, larger on one side of the midrib than the other, in other words asymmetrical.
oblong
length a few times greater than width, with sides almost parallel and ends rounded.
obovate
of a leaf, a 2-dimensional shape of which the length is about 1.5 times the width, and widest above the centre.
obsolete
not evident, or at most rudimentary or vestigial.
obtuse
blunt or rounded; converging edges making an angle of more than 90°; compare acute. See Leaf shape.
ocrea (ochrea)
a sheath, formed from two stipules, encircling the node in Polygonaceae.
odd-pinnate
(imparipinnate) having an odd number of leaflets in a compound leaf.
oft.
often. Compare usu. and s.t.
-oideae
The suffix added to the stem of a generic name to form the name of a subfamily: for instance, FumariaFumarioideae.
olim
formerly, e.g., "olim B", formerly in the Berlin herbarium (Herbarium Berolinense).
ontogeny
the sequence of developmental stages through which an organism passes.
opera utique oppressa (plural), and opus utique oppressum (singular)
listed after the botanical name of a plant, or the name of a publication, this indicates that a publication is listed in the International Code of Nomenclature for algae, fungi, and plants as a suppressed work. Botanical names of the specified rank in the publication are considered not validly published (article 34).
operculum (calyptra)
a lid or cover that becomes detached at maturity, e.g. in Eucalyptus, a cap covering the bud and formed by the fusion or cohesion of perianth parts.
opposite
(as adjective) leaves or flowers borne at the same level but on opposite sides of the axis; or when something occurs on the same radius as something else, for example anthers opposite sepals; compare alternate.
orbicular
flat and more or less circular.
order
a group of one or more families sharing common features, ancestry, or both.
ortet
the original single parent plant from which a clone ultimately derives.
orthotropous
when an ovule is erect, with the micropyle directed away from the placenta; atropous; cf. amphitropous, anatropous, campylotropous.
oval
see elliptical.
ovary
the basal portion of a carpel or group of fused carpels, enclosing the ovule(s).
ovate
shaped like a section through the long-axis of an egg and attached by the wider end.
ovoid
egg-shaped, with wider portion at base; 3-dimensional object, ovate in all sections through long-axis.
ovule
loosely, the seed before fertilization; a structure in a seed plant within which one or more megaspores are formed (after fertilization it develops into a seed).

P

pachycaul
with a disproportionately thick trunk
This Senecio articulatus is pachycladous because of its disproportionately thick stem.
pachycladous
with disproportionately thick stems
palea

1. the upper of two bracts enclosing a grass flower, major contributors to chaff in harvested grain.
2.  Chaffy scales on the receptacles of many Asteraceae.
3.  Chaffy scales on the stipe of many ferns.
paleate
bearing paleae or chaffy scales, as in description of the receptacle of a capitulum of a plant in the Asteraceae.
paleaceous
Chaff-like in texture.
A maple (Acer platanoides leaf is palmate because the veins radiate out from a central point, like fingers from the palm of a hand.
palmate
1.  leaf with veins radiating out from a central point (usually at the top of a petiole), resembling spread out fingers pointing away from the palm.
2.  A compound palmate leaf has leaflets that radiate from a central point (usually at the top of a petiole).
palmatifid
deeply divided into several lobes arising from more or less the same level.
palmatisect
intermediate between palmate and palmatifid, i.e. the segments are not fully separated at the base; often more or less digitate.
panicle
(adjective paniculate) a compound raceme; an indeterminate inflorescence in which the flowers are borne on branches of the main axis or on further branches of these.
papilionate
butterfly-like; with a corolla like that of a pea.
papilla
(plural papillae, adjective papillose, papillate) a small, elongated protuberance on the surface of an organ, usually an extension of one epidermal cell.
pappus
in daisy florets, a tuft or ring of hairs or scales borne above the ovary and outside the corolla (representing the reduced calyx); a tuft of hairs on a fruit.
paraperigonium
Also paraperigone. Anomalous secondary outgrowth of the perianthal meristem with ramifying vasculature. See also perigonium, perianth and corona

[6]

parasite
an organism living on or in a different organism, from which it derives nourishment; compare saprophyte, epiphyte.
parenchyma
a versatile ground tissue composed of living primary cells that performs a wide variety of structural and biochemical functions in plants.
parietal
attached to the marginal walls of a structure, for example ovules attached to placentas on the wall of the ovary. See Placentation.
paripinnate
having an even number of leaflets (or pinnae), that is terminated by a pair of pinnae as opposed to a single pinna; compare imparipinnate.
parthenocarpy
the development or production of fruit without fertilization. compare stenospermocarpy.
patent
Spreading, erect, standing at 90o to the axis. See also erecto-patent, patulous.
patulous
patent.
pauciflor
having few flowers per inflorescence. See also pluriflor and uniflor.
pectinate
pinnately divided with narrow segments closely set like the teeth of a comb.
pedate
with a terminal lobe or leaflet, and on either side of it an axis curving outwards and backwards, bearing lobe or leaflets on the outer side of the curve.
pedicel
(adjective pedicellate) the stalk of a flower. May be applied to the stalk of a capitulum in Asteraceae
peduncle
(adjective pedunculate) the stalk of an inflorescence.
peltate
shield-like; with stalk attached to the lower surface and not to the margin.
pellucid
transmitting light; for example, said of tiny gland dots in the leaves of e.g. Myrtaceae and Rutaceae that are visible when held in front of a light.
pendulous
hanging, for example an ovule attached to a placenta on the top of the ovary; compare suspended.
penicillate
tufted like an artist's brush; with long hairs towards one end.
penninervation (penninerved)
with pinnately arranged veins.
pentamerous
in five parts, particularly with respect to flowers, five parts in each whorl. See also trimerous and tetramerous.
pepo
type of berry formed from an inferior ovary and containing many seeds, usually large with a tough outer skin, for instance, pumpkin, cucumber.
perennating
of an organ that survives vegetatively from season to season. A period of reduced activity between seasons is usual.
perennial
a plant whose life span extends over several years.
perfect
of a flower, when bisexual.
perfoliate
with its base wrapped around the stem (so that the stem appears to pass through it), e.g. of leaves and bracts.
The leaves of Aponogeton madagascariensis are perforate.
perforate
with many holes. Used to describe the texture of pollen exine, and also to indicate that tracheary elements have a perforation plate. See also fenestrate.
perforation plate
in a tracheary element, part of the cell wall that is perforated; present in vessel members but not in tracheids. Should not be confused with a pit.
perianth
the collective terms for the calyx and corolla of a flower (generally used when the two are similar). Abbreviation: P. For instance P 3+3 indicates the calyx and corolla each have 3 elements, or 3 sepals + 3 petals
pericarp
the wall of a fruit, developed from the ovary wall.
periclinal
Curved along parallel to a surface, cf. anticlinal.
The perigonium of a moss (red in this case), also called a spash-cup, surrounds the antheridia and aids in dispersal of sperm
perigonium
in flowering plants see perianth
2.  in mosses, the leaves surrounding the antheridia, also called a spash-cup, e.g. in Polytrichum juniperinum.
perigynium
a sac around the pistillate flower of sedges
perigynous
borne around the ovary, i.e. of perianth segments and stamens arising from a cup-like or tubular extension of receptacle (free from the ovary but extending above its base); cf. epigynous, hypogynous.
persistent
remaining attached to the plant beyond the usual time of falling, for instance sepals not falling after flowering, flower parts remaining through maturity of fruit; compare deciduous, caducous.
perule (lat. perula, perulae)

1.  the scales covering a leaf or flower bud, or a reduced scale like leaf surrounding the bud. Buds lacking perulae are referred to as 'naked'
2.  in Camellias the final bracts and sepals become indistinguishable and are called perules.
3.  a kind of sac formed by the adherent bases of the two lateral sepals in certain orchids.
petal
in a flower, one of the segments or divisions of the inner whorl of non-fertile parts surrounding the fertile organs, usually soft and conspicuously coloured; compare sepal.
petaloid
like a petal; soft in texture and coloured conspicuously.
petiolate
a leaf with a petiole. Compare sessile.
petiole
the stalk of a leaf.
petiolule
the stalk of a leaflet.
petricolous
Rock-dwelling; living on or among rocks.
phanerogam
gymnosperms and angiosperms; plants producing stamens and gynoecia; literally plants with conspicuous sexual reproductive organs; cf. cryptogams.
phenology
the study of the timing of seasonal biological phenomena, such as flowering, leaf emergence, fruit ripening and leaf fall.
phloem
a specialised conducting tissue in vascular plants that transports sucrose from the leaves to other plant organs.
photobiont
In a lichen, the component that does the photosynthesis, the green algae (Chlorophyta) or blue-green algae (Cyanobacteria). (compare to mycobiont, the fungal component.) Also called the phycobiont.
photosynthesis
the process by which sugars are made from carbon dioxide and water in cells containing chloroplasts.
phycobiont
In a lichen, a synonym for photobiont
phyllid
A leaf-like extension of the stem in Bryophytes
phyllode
(adjective phyllodineous) a leaf with the blade much reduced or absent, and in which the petiole and or rachis perform the functions of the whole leaf; e.g. many acacias; cf. cladode.
phyllopodium
(in ferns) a short outgrowth of the stem on which the frond is borne and that remains attached to the rhizome after the frond has been shed.
phyllosphere
the above-ground surface of plants as a habitat for epiphytic microorganisms.
phytomelan
also phytomelanin. A black, inert, organic material that forms a crust-like covering of some seeds, commonly found in Asparagales, Asteraceae, etc. Adjective=phytomelanous
pilose
covered with soft, weak, thin and clearly separated hairs, which are usually defined as long and sometimes ascending.
pinna
(plural pinnae) a primary segment of a compound leaf.
pinnate
a compound leaf with leaflets arranged on each side of a common petiole or axis; also applied to how the lateral veins are arranged in relation to the main vein.
pinnatifid
pinnately lobed.
pinnatisect
pinnately divided almost to midrib but segments still confluent.
pinnule
ultimate free division (or leaflet) of a compound leaf, or a pinnate subdivision of a multipinnate leaf.
pistil
1.  a single carpel when the carpels are free.
2.  a group of carpels when the carpels are united by the fusion of their walls.
pistillate flower
a flower containing pistils but no stamens
Tracheid of oak shows pits along the cell walls.
pit
in tracheary elements, a section of the cell wall where the secondary wall is missing, and the primary wall is present. Pits generally occur in pairs and link two cells.
pith
the central region of a stem, inside the vascular cylinder; the spongy parenchymatous central tissue in some stems and roots.
placenta
the tissue within an ovary to which the ovules are attached.
placentation
the arrangement of ovules inside ovary; for example axile, free-central, parietal, marginal, basal, or apical.
This crustose lichen, Caloplaca thallincola, is placodioid because of the radiating arms in its growth pattern.
placodioid
The form of a lichen thalus which radiates outward with the ends of the radiating arms peeling up from the substrate, but which lack a cortex on the underside (unlike foliose lichens).
Plant Breeders Rights (PBR)
these rights, governed by Plant Breeder's Rights Acts give the plant breeder legal protection over the propagation of a cultivar, and the exclusive rights to produce and to sell it, including the right to license others to produce and sell plants and reproductive material of a registered, deliberately bred variety. Cf. UPOV.
Plant Variety Rights (PVR)
governed by the Plant Variety Rights the registration of new varieties is now governed by Plant Breeders Rights.
Plastochron
the time between successive leaf initiation events.
plicate
pleated; folded back and forth longitudinally like a fan, such as the leaves of many palm species. The concept often appears in specific names in forms such as Aloe plicatilis and Acacia plicata. Commonly such names are not correctly appropriate, but are applied to distichous structures rather than plicate.
-plinerved
(of leaves) a suffix indicating that the main nerves are lateral and arise from a point distinctly above the base of the leaf. Combined with a numerical prefix to form words like 3-plinerved, 5-plinerved, and so on. Such leaves are especially characteristic of the family Melastomataceae.
plumose
like a feather; with fine hairs branching from a main axis.
plumule
the part of an embryo that gives rise to the shoot system of a plant; cf. radicle.
pluriflor
having many flowers per inflorescence. See also pauciflor and uniflor.
pluriovulate
having many ovules as in placentae, carpels or ovaries.
pneumatophore
a vertical, aerial (at low tide) appendage to the roots of some plants, through which gases are exchanged; e.g. on mangroves.
pod
1.  a legume, the fruit of a leguminous plant, a dry fruit of a single carpel, splitting along two sutures.
2.  siliqua and silicula, the fruit of Brassicaceae, a dry fruit composed of two carpels separated by a partition.
pollen
powdery mass shed from anthers (of angiosperms) or microsporangia (of gymnosperms); the microspores of seed plants; pollen-grains.
pollen-mass
pollen-grains cohering by a waxy texture or fine threads into a single body; pollinium; e.g. in orchids.
pollen transmitting tissue
the tissue in the style of a flower through which the pollen tubes grow.
pollination
the transfer of pollen from the male organ (anther) to the receptive region of a female organ (stigma).
pollinium
see pollen-mass.
polygamodioecious
having bisexual and male flowers on some plants and bisexual and female flowers on others; cf. androdioecious, andromonoecious, dioecious, monoecious, polygamomonoecious, polygamous.
polygamomonoecious
having male, female and bisexual flowers on the same plant; cf. androdioecious, andromonoecious, polygamodioecious, polygamous.
polygamous
having bisexual and unisexual flowers on the same plant.
polymorphic
of several different kinds (in respect to shape and/or size), hence polymorphism. See also monomorphic (a single type) and dimorphic (two types)
polyploid
with more than two of the basic sets of chromosomes in the nucleus; any sporophyte with cells containing three or more complete sets of chromosomes. Various combinations of words or numbers with '-ploid' indicate the number of haploid sets of chromosomes; e.g. triploid = 3 sets, tetraploid = 4 sets, pentaploid = 5 sets, hexaploid = 6 sets, and so on.
polystemonous
having numerous stamens; the number of stamens being at least twice the number of sepals or petals, but not strictly three or four times that number.
pome
a fruit that has developed partly from the ovary wall but mostly from the hypanthium, e.g., apple.
population
1.  all individuals of one or more species within a prescribed area.
2.  a group of organisms of one species, occupying a defined area and usually isolated to some degree from other similar groups.
3.  in statistics, the whole group of items or individuals under investigation.
poricidal
opening by pores, like the capsule of a poppy, or like the anthers in several families of plants. compare: longicidal
posterior
positioned behind, towards the rear, proximal; compare anterior, distal.
prickle
(adjective: prickly) hard, pointed outgrowth from the surface of a plant (involving several layers of cells but not containing a vein); sharp outgrowth from the bark, detachable without tearing wood; cf. thorn.
primary species
In lichens, a species reproducing mainly by sexual reproduction, not vegetative reproduction.
primary vein
(venation) the single vein or array of veins that are conspicuously larger than any others in the leaf. In pinnate venation, the single primary vein is in the middle of the leaf. In palmate venation, several such veins radiate from a point at or near the base of the leaf.
propagule
In lichens, a part of the thallus that has both fungal and algal parts and can break off for vegetative reproduction, e.g., an isidium, phyllidium, phyllocladium, or soredium).
prophyll
a leaf formed at the base of a shoot, usually smaller than those formed later.
pro parte
(Latin) in part; in nomenclature, to denote that the preceding taxon includes more than one currently recognized entity, and that only one of those entities is being considered.
procumbent
spreading along the ground but not rooting at the nodes: not as close to ground as prostrate.
propagules
a structure capable of producing a new plant; includes seeds, spores, bulbils, etc.
prostrate
lying flat on the ground.
protandrous
male sex organs maturing before the female ones, e.g. a flower shedding pollen before the stigma is receptive; cf. protogynous.
proteranthous
new leaves appear before flowers. See also hysteranthous and synanthous
prothallus
a #gametophyte plant, usually flattened and delicate; e.g. in ferns and fern allies.
protogynous
female sex organs maturing before the male ones, e.g. a flower shedding pollen after the stigma has ceased to be receptive; cf. protandrous.
proximal
near the point of origin or attachment, cf. distal.
pruinose
covered with a powdery, waxy material; with a bloom.
pseudanthium
a particular form of inflorescence occurring in the Asteraceae and Euphorbiaceae, in which multiple flowers are grouped together to form a flower-like structure, commonly called a head or capitulum.
pseudo
false; not genuine; e.g. pseudo-bulb = a thickened, bulb-like internode in orchids, or a corm.
pseudostipule
an enlarged, persistent axillary bud scale that resembles a stipule; common in Bignoniaceae.
pseudoverticillate
having the appearance of being whorled (verticillate), without actually being so.
puberulous (puberulent)
covered with minute soft erect hairs.
pubescent
downy; covered with short, soft, erect hairs.
pulverulent
having powdery or crumbly particles as if pulverized.
pulvinate
with a pulvinus
pulvinus
a swelling at either end of a petiole of a leaf or petiolule of a leaflet, e.g. in Fabaceae, that permits leaf movement.
punctate
marked with dots.
punctiform
dot-like
pungent
having a sharp hard point.
pustule
A blister-like swelling.
pustulate
Having pustules.
pyramidal
of a plant's form, tetrahedral, pyramid-shaped.
pyrene
the stone of a drupe, consisting of the seed surrounded by the hardened endocarp.
pyriform
pear-shaped; a term for solid shapes that are broadest in the upper third and abruptly narrowed near the base.

Q

quadrate
more or less square.

R

raceme
(adjective racemose) an indeterminate inflorescence in which the main axis produces a series of flowers on lateral stalks, the oldest at the base and the youngest at the top; cf. spike.
rachilla (rhachilla)
the axis of a grass spikelet, above the glumes.
rachis
(plural rachises; rachides) the axis of an inflorescence or a pinnate leaf; for example ferns; secondary rachis is the axis of a pinna in a bipinnate leaf distal to and including the lowermost pedicel attachment.
radial
with structures radiating from a central point as spokes on a wheel, for example, the lateral spines of a cactus.
radiate
of daisies, of a capitulum, with ray florets surrounding disc florets.
radical
springing from the root; clustered at base of stem.
radicle
the part of an embryo giving rise to the root system of a plant; cf. plumule.
rainforest
a moist temperate or tropical forest dominated by broad-leaved trees that form a continuous canopy.
ramet
an individual member of a clone.
1.  zygomorphic (ligulate) flowers in a radiate flowerhead, that is, ray-florets/flowers, for example Asteraceae.
2.  each of the branches of an umbel.
receptacle
the axis of a flower, in other words, floral axis; torus; for example in Asteraceae, the floral base or receptacle is the expanded tip of the peduncle on which the flowers are inserted.
recurved
bent or curved backwards or downwards.
reduplicate
folded outwards, or with the two abaxial surfaces together.
reflexed
bent sharply back or down.
registered name
a cultivar name accepted by the relevant International Cultivar Registration Authority.
registration
1.  the act of recording a new cultivar name with an International Cultivar Registration Authority.
2.  recording a new cultivar name with a statutory authority like the Plant Breeder’s Rights Office.
3.  recording a trademark with a trade marks office.
regular
see actinomorphic.
reniform
kidney-shaped.
resupinate
1.  In botany, describing leaves or flowers that are in an inverted position because the petiole or pedicel, respectively, is twisted 180 degrees. compare: #hyper-resupinate
2.  In lichenology, referring to either having or being a fruiting body that lies flat on the substrate, with the hymenium either over the whole surface or at the periphery.
reticulate
forming a network (or reticulum), e.g. veins that join one another at more than one point.
retrorse
bent backwards or downwards; cf. antrorse.
retuse
with a blunt (obtuse) and slightly notched apex.
revision
an account of a particular plant group, like an abbreviated or simplified monograph. Sometimes confined to the plants of a particular region. Similar to a monograph in clearly distinguishing the taxa and providing a means for their identification; compare monograph.
revolute
rolled under (downwards or backwards), for example when the edges of leaves are rolled under towards the midrib; compare involute.
rhachis
see rachis.
rhizine
The "root" or "trunk" projection of a foliose lichen that attaches the lichen to the substrate (what the lichen is growing on)
rhizodermis
the root epidermis, the outermost primary cell layer of the root
rhizome
a perennial underground stem usually growing horizontally. See also stolon. Abbreviation: rhiz.
rhizosphere
the below-ground surface of plants and adjacent soil as a habitat for microorganisms.
rhombic
like a rhombus: an oblique figure with four equal sides; compare trapeziform, trullate.
rhomboid
a four-sided figure with opposite sides parallel but with adjacent sides an unequal length (like an oblique rectangle); see also rhombic.
rhomboidal
a shape, for instance of a leaf, that is roughly diamond-shaped with length equal to width.
rimose
with many cracks, as in the surface of a crustose areolate lichen.
root
a unit of a plant's axial system which is usually underground, does not bear leaves, tends to grow downwards, and is typically derived from the radicle of the embryo.
root hairs
outgrowths of the outermost layer of cells just behind the root tips, functioning as water-absorbing organs.
root microbiome
the dynamic community of microorganisms associated with plant roots.
rootstock
1. the part of a budded or grafted plant which supplies the root system, also simply called a stock.
2.  plants selected to produce a root system with some specific attribute, e.g. a virus-free rootstock.
rosette
when parts are not whorled or opposite but appear so, due to the contractions of internodes, e.g. the petals in a double rose or a basal cluster of leaves (usually close to the ground) in some plants.
rostrate
with a beak.
rotate
circular and flattened; for example a corolla with a very short tube and spreading lobes (for instance some Solanaceae).
ruderal
a plant that colonises or occupies disturbed waste ground. See also weed.
The runcinate lobes of a Taraxacum officinale leaf point downwards
rudimentary
poorly developed and not functional; compare vestigial.
rugose
wrinkled.
rugulose
finely wrinkled.
ruminate
(usually applied to endosperm). irregularly grooved or ridged; appearing chewed. (a common type of endosperm in Myristicaceae).
runcinate
sharply pinnatifid or cleft, the segments directed downward.
runners
see stolon.
rupicolous
rupestral, saxicolous, growing on or among rocks. (compare epilithic, lithophytic)
rush
a plant belonging to the family Juncaceae or, more loosely, applied to various monocotyledons.

S

saccate
pouched or shaped like a sack.
sagittate
shaped like the head of an arrow; narrow and pointed but gradually enlarged at base into two straight lobes directed downwards; may refer only to the base of a leaf with such lobes; cf. hastate.
salverform
trumpet-shaped; with a long, slender tube and a flat, abruptly expanded limb.
samara
a dry, indehiscent fruit with its wall expanded into a wing, e.g. in the genus Acer.
samphire
a common name given to various edible coastal plants, such as Salicornia spp. (Amaranthaceae), Crithmum maritimum (Apiaceae) and Limbarda crithmoides (Asteraceae).
saprophyte
(adjective saprophytic) an organism deriving its nourishment from decaying organic matter and usually lacking chlorophyll; compare parasite, epiphyte.
sarmentose
having long, slender, prostrate stolons (runners).
This Caloplaca marina lichen is saxicolous because it grows on stone.
saxicolous
growing on stone, like some lichens.
scabrid (scabrous)
rough to the touch with short hard emergences or hairs.
scalariform
ladderlike in structure or appearance.
scale
1.  a reduced or rudimentary leaf, for example around a dormant bud.
2.  a flattened epidermal outgrowth, such as those commonly found on the leaves and rhizomes of ferns.
scandent
climbing, by whatever means. See also: scandent in Wiktionary.
scape
(adjective scapose) a stem-like flowering stalk of a plant with radical leaves.
scapose
having the floral axis more or less erect with a few leaves or devoid of leaves; consisting of a scape.
scarious
dry and membranous.
schizocarp
a dry fruit formed from more than one carpel but breaking apart into individual carpels (mericarps) when ripe.
scion
the aerial part of a graft combination, induced by various means to unite with a compatible understock/rootstock.
sclereid
a cell with a thick, often lignified, cell wall that is shorter than a fiber cell and dies soon after the thickening of its cell wall.
sclerenchyma
a strengthening or support tissue composed of sclereids or of a mixture of sclereids and fibers.
sclerophyll
(adjective sclerophyllous) a plant with hard, stiff leaves; leaves stiffened with thick-walled cells.
scorpioid
of a cymose inflorescence, when it branches alternately on one side and then the other; cf. helicoid.
scrobiculate
with very small pits.
scrubland
dense vegetation dominated by shrubs.
scurf
minute loose, membranous scales on the surface of some plant parts e.g. leaves.
secondary metabolite
chemicals produced by a plant that do not have a role in "primary" functions such as growth, development, photosynthesis, reproduction, etc.
secondary species
In lichens, a "species" taxon of lichen reproducing only by vegetative means, whose components reproduce mainly by sexual means – cf. primary species.
secretory tissue
the tissues concerned with the secretion of gums, resins, oils and other substances in plants.
section (sectio)
the category of supplementary taxa intermediate in rank between subgenus and series. It is a singular noun always written with a capital initial letter, in combination with the generic name.
secund
with all the parts grouped on one side or turned to one side (applied especially to inflorescences).
sedge
a plant belonging to the family Cyperaceae.
seed
a ripened ovule, consisting of a protective coat enclosing an embryo and food reserves; a propagating organ formed in the sexual reproductive cycle of gymnosperms and angiosperms (together, the seed plants).
segment
part or subdivision of an organ, for example a petal is a segment of the corolla. A term sometimes used when the sepals and petals are indistinguishable.
self-pollination
also called selfing, the acceptance by stigmas of pollen from the same flower or from flowers on the same plant, which means they are self-compatible.
semelparity
When a plant flowers once then dies.
semiterete
(or semi-terete), rounded on one side, but flat on the other. See also terete
sensitive
a descriptive term for stigmas that, in response to touch, close the two lobes of the stigma together, ending the receptivity of the stigma, at least for the time that the lobes are closed together. Mimulus is perhaps the best-known example.
sensu
in the sense of.
sensu lato
of a plant name, in its broadest sense.
sensu stricto
of a plant name, in its narrowest sense.
sepal
in a flower, one of the segments or divisions of the outer whorl of non-fertile parts surrounding the fertile organs, usually green; compare petal.
septicidal
of a fruit, when it dehisces along the partitions between loculi; cf. loculicidal.
septum
(plural septa) a partition, for example the membranous wall separating the two valves of the pod of Brassicaceae.
seriate
arranged in rows.
sericeous
silky with dense appressed hairs.
series
the category of supplementary taxa intermediate in rank between section and species. It is a plural adjective; for instance Primula subgenus Primula sect. Primula series Acaules.
serrate
toothed with asymmetrical teeth pointing forward; like the cutting edge of a saw.
serrulate
finely serrate.
sessile
attached without a stalk, e.g. of a leaf without a petiole or a stigma, when the style is absent.
seta
(adjectives setose, setaceous) a bristle or stiff hair (in Bryophytes, the stalk of the sporophyte); a terminal seta is an appendage to the tip of an organ, e.g. the primary rachis of a bipinnate leaf in Acacia.
sheath
a tubular or rolled part of an organ, e.g. the lower part of the leaf in most grasses.
shoot
usually the aerial part of a plant; a stem including its dependent parts, leaves flowers etc.
shrub
a woody perennial plant without a single main trunk, branching freely, and smaller than a tree.
sigmoid
shaped like the letter 'S'.
silicula
a stout siliqua (not more than twice as long as wide).
siliqua
a dry, dehiscent fruit (more than twice as long as wide) formed from a superior ovary of two carpels, with two parietal placentas and divided into two loculi by a 'false' septum.
silky
densely covered with fine soft straight appressed hairs, with a lustrous sheen and satiny to the touch.
silviculture
the science of forestry and the cultivation of woodlands for commercial purposes and wildlife conservation.
simple
undivided, for instance a leaf not divided into leaflets (note, however, that a simple leaf may be entire, toothed or lobed) or an unbranched hair or inflorescence.
sinuate
with deep, wave-like depressions along the margins, but more or less flat; compare undulate.
sinus
a notch or depression between two lobes or teeth in the margin of an organ.
solitary
single, of flowers that grow one plant per year, one in each axil, or widely separated on the plant; not grouped in an inflorescence.
soralia
In a lichen, the structure that bears soredium for non sexual reproduction.
soredia
plural of soredium
soredium
In a lichen, a small groups of algal cells surrounded by fungal filaments that form in soralia, which break off and grow new lichens without sexual reproduction after being dispersed by wind. Compare to an isidium, which breaks off and is dispersed by mechanical means.
sp.
abbreviation of species (singular), often used when the genus is known but the species has not been determined, as in Brassica sp.
spp.
abbreviation of species (plural). See sp.
spadix
a spicate (spike-like) inflorescence with a stout, often succulent axis.
spathe
(adj. spathaceous), a large bract ensheathing an inflorescence. Traditionally any broad flat blade.
spathulate (spatulate)
spoon-shaped; broad at the tip with a narrowed projection extending to the base.
species
a group, or populations of individuals, sharing common features and/or ancestry, generally the smallest group that can be readily and consistently recognized; often, a group of individuals capable of interbreeding and producing fertile offspring. The basic unit of classification, the category of taxa of the lowest principal rank in the nomenclatural hierarchy.
specific epithet
follows the name of the genus, and is the second word of a botanical binomial. The generic name and specific epithet together constitute the name of a species; i.e. the specific epithet is not the species name.
spica
(adjective spicate) a spike.
spike
(adjective spicate) an unbranched, indeterminate inflorescence in which the flowers are without stalks; cf. raceme.
spikelet
a unit of the inflorescence especially in grasses, sedges and some other monocotyledons, consisting of one to many flowers and associated bracts (glumes).
spine
(adjective spinose) a stiff, sharp structure, formed by the modification of a plant organ that contains vascular tissue; e.g. a lateral branch or a stipule; includes thorns.
spinescent
ending in a spine; modified to form a spine.
spiral
of arrangement, when plant parts are arranged in a succession of curves like the thread of a screw, or coiled in a cylindrical or conical manner.
splash-cup (sporangia)
A cup-like structure in cryptograms for spore dispersal whereby energy of raindrops hitting into the cup splash back out carrying the spore.[7]
sporangium (sporangia)
a structure in which spores are formed.
sporangiophore
an organ bearing sporangia, e.g. in the cones of Equisetum.
spore
a haploid propagule, produced by meiosis in diploid cells of a sporophyte that can germinate to produce a multicellular gametophyte.
sporocarp
a fruiting body containing spores.
sporophyll
a modified leaf that bears a sporangium or sporangia, in pteridophytes.
sporophyte
the haploid multicellular phase in the alternation of generations of plants and algae that produces the spores; cf. gametophyte.
sport
a naturally occurring variant of a species, not usually present in a population or group of plants; a plant that has spontaneously mutated so that it differs from its parent plant.
spreading
extending horizontally, for example branches; standing out at right angles to axis, for example leaves or hairs.
spur
1.  a short shoot.
2.  a conical or tubular outgrowth from the base of a perianth segment, often containing nectar.
squamule
(plural squamules, squamulae) small scales; In lichens, squamules are overlapping plate-like forms, sometimes overlapping so much as to become leaf-like, but which lack a lower cortex, unlike the leafy forms of foliose lichens – adjective: squamulose
squamulose
Covered with small scales (squamules). In lichens, being composed of squamules
squarrose
with tips of leaves, stems etc. radiating or projecting outwards as in the moss Rhytidiadelphus squarrosus.
s.t.
abbreviation for sometimes, compare usu. and oft.
stalk
the supporting structure of an organ, usually narrower in diameter than the organ.
stamen
(adjective staminate) male organ of a flower, consisting (usually) of a stalk (filament) and a pollen-bearing portion (anther).
staminate flower
a flower with stamens but no pistil
staminode
a sterile stamen, often rudimentary, sometimes petal-like.
standard
the large posterior petal of pea-flowers.
standard specimen
a representative specimen of a cultivar (or other taxon), one that demonstrates how the name of that taxon should be used.
stele
the primary vascular system (phloem, xylem and ground tissue) of plant stems and roots.
stellate
star-shaped, for example a type of hair.
stem
the plant axis, either aerial or subterranean, which bears nodes, leaves, branches and flowers.
stem-clasping
see amplexicaul.
stenospermocarpy
the development or production of fruit that is seedless or has minute seeds because of the abortion of seed development. compare parthenocarpy
sterile
infertile, for example a stamen that does not bear pollen, or a flower that does not bear seed.
stigma
the pollen-receptive surface of a carpel or group of fused carpels, usually sticky; usually a point or small head at the summit of the style.
stipe
in ferns, the stalk of a frond; generally a small stalk.
stipella
(stipel; plural stipellae) one of two small secondary stipules at the base of leaflets in some species.
stipitate
stalked; borne on a stipe; of an ovary, borne on a gynophore.
stipulate
bearing stipules.
stipule
small appendage at the bases of leaves in many dicotyledons.
stolon
slender, prostrate or trailing stem, producing roots and sometimes erect shoots at its nodes. See also rhizome.
stock
see rootstock.
stoloniferous
having stolons.
stoma
(plural stomata) a pore; small hole in the surface of a leaf (or other aerial organ) allowing the exchange of gases between tissues and the atmosphere.
striate
striped with parallel, longitudinal lines or ridges.
strigose
covered with appressed, rigid, bristle-like, straight hairs; the appressed equivalent of hispid.
strobilus
(plural strobili) a cone-like structure consisting of sporophylls (e.g. conifers and club mosses) or sporangiophores (e.g. in Equisetopsida) borne close together on an axis.
style
an elongated part of a carpel, or group of fused carpels, between the ovary and the stigma.
stylodium
an elongate stigma that resembles a style, a false style, e.g. commonly found in Poaceae and Asteraceae.
stylulus
the elongated apex of a free carpel which functions like the style of a syncarpous ovary, allowing pollen tubes from its stigma to enter the locule of only that carpel.
subcoriaceous
slightly leathery or coriaceous.
subgenus
the category of supplementary taxa intermediate between genus and section. It is a singular noun, always has a capital initial letter and is used in combination with the generic name; e.g. Primula subgenus Primula.
subglobose
Inflated, but less than spherical. See also globose.
subshrub
undershrub; small shrub which may have partially herbaceous stems, but generally a woody plant less than 1 m high.
subspecies
a grouping within a species, usually used for geographically isolated and morphologically distinct entities. Its taxonomic rank occurs between species and variety.
subtend
to stand beneath or close to, as in a bract at the base of a flower.
subquadrangular
not quite square; see also quadrangular in wiktionary.
subulate
narrow and tapering gradually to a fine point.
succulent
juicy, fleshy; a plant with a fleshy habit.
sucker
a shoot of more or less subterranean origin; an erect shoot originating from a bud on a root or a rhizome, sometimes at some distance from the stem of the plant.
suffrutex
subshrub or undershrub.(plural suffrutices). See also suffrutex for etymology etc.
sulcate
furrowed; grooved. May be single (monosulcate), two (bisulcate) or many (polysulcate)
superficial
on the surface.
superior
of an ovary, borne above the level of attachment of the other floral parts, or above the base of a hypanthium; compare inferior, half-inferior.
suspended
of an ovule, when attached slightly below the summit of the ovary; compare pendulous.
suture
a junction or seam of union. (see fissure, commissure)
sward
extensive, more or less even cover of a surface, for example a lawn grass; compare tussock.
sympatric
with more or less similar or overlapping ranges of distribution.
sympodial
a mode of growth in which the main axis is repeatedly terminated, and replaced with a lateral branch. Examples occur in the family Combretaceae, including the genera Terminalia and Combretum
syconium
a hollow infructescence containing multiple fruit, such as that of a fig.
syn- (sym-)
with, together.
symmetrical
capable of being divided into at least two equal, mirror-image halves (e.g. zygomorphic) or to have rotational symmetry (e.g. regular, actinomorphic). Contrast with irregular, asymmetrical.
sympetalous
with united (connate or fused) petals.
synangium
a fused aggregate of sporangia, e.g. in the trilocular (=with three chambers) sporangia of the whisk fern Psilotum.
synanthous
new leaves and flowers appear and die back at the same time. See also hysteranthous and proteranthous
synaptospermy
The dispersal of diaspores as units, where each bears more than one seed, for example where each diaspore comprises an entire inflorescence, as in Brunsvigia or multi-seeded fruit as in Tribulus zeyheri. Ephemeral synaptospermy is the term for when the diaspores split into units containing fewer or single seeds each, as in most tumbleweeds. True synaptospermy is when the diaspore generally remains entire until germination, as commonly happens in species of Grielum.
syncarpous
of a gynoecium, made up of united carpels.
synonym
outdated name or 'alternative' name for the same taxon.
synoecious
Synonym of bisexual.

T

taproot
the main, descending root of a plant with a single dominant root axis.
tartareous
having a surface that is course, thick, rough, and crumbling.
taxon
(plural taxa) a group or category in a system of classification, derived from the Greek prefixes taxo-, taxis- meaning arrangement.
taxonomy
the study of the principles and practice of classification.
tegmen
the inner layer of the testa (seed coat). It develops from the inner integument of the ovule.
tendril
a slender organ (modified e.g. from stem, leaf, leaflet or stipule) used by climbing plants to cling to an object.
tepal
perianth segment, either sepal or petal; usually used when all perianth segments are similar in appearance; cf. petal.
terete
circular in cross-section; more or less cylindrical without grooves or ridges. Also semiterete.
terminal
situated at the tip or apex.
ternate
in groups of three; of leaves, arranged in whorls of three; of a single leaf, with the leaflets arranged in groups of three. See Leaf shape.
terrestrial
generally denotes of or on the ground; of habitat, on land as opposed to in water (aquatic) or on rocks (lithophytic), or other plants (epiphytic), and so on.
testa
seed coat.
tetrad
a group of four; usually means four pollen grains remaining fused together a maturity, e.g. in the Epacridaceae.[8]
tetragonal
square, with four corners, four-angled, e.g. the cross section of the stems of herbaceous Lamiaceae.
tetramerous
in four parts, particularly with respect to flowers, four parts in each whorl. See also trimerous and pentamerous.
tetraploid
having four complete sets of chromosomes in each sporophyte cell.
tetraspore
the asexual spore of red algae. It is so named because each sporangium produces just four spores. See Rhodophyceae.[9]
thalamus
obsolete. 1) see receptacle; 2) the inflorescence disk of Asteraceae; 3) as used by Carl Linnaeus, the calyx
thallus
The "vegetative" part (part other than sexual fruitbodies) of a lichen that has both the fungus (mycobiont) and photobiont; plural thalli
theca
one of the usually two synangia in which pollen is produced in flowering plants. It consists of two fused sporangia known as pollen sacs. The wall between the pollen sacs disintegrates before dehiscence, which is usually by a common slit.
thorn
a sharp, stiff point, usually a modified stem, that cannot be detached without tearing the subtending tissue; a spine; cf. prickle.
throat
the opening of a corolla or perianth.
thyrse
a branched inflorescence in which the main axis is indeterminate (racemose) and the lateral branches determinate (cymose).
tomentum
(adjective tomentose) a dense covering of short, matted hairs. Tomentose is often used as a general term for bearing an indumentum, but this is not a recommended use.
toothed
with a more or less regularly incised margin.
torus
see receptacle.
transmitting tissue
see pollen transmitting tissue.
trapeziform
1.  like a trapezium (a four-sided figure with two parallel sides of unequal length)
2.  like a trapezoid (a four-sided figure, or quadrilateral, with neither pair of sides equal); sometimes used erroneously as a synonym for rhombic.
tree
a woody plant, usually with a single distinct trunk and generally more than 2-3 m tall.
triad
a group of three.
triangular
planar and with 3 sides.
tribe
a taxonomic grouping, in rank between genus and family.
trichome
in non-filamentous plants, any hair-like outgrowth from epidermis, e.g. a hair or bristle; sometimes restricted to unbranched epidermal outgrowths.
trifid
split into three parts. See also bifid.
trifoliolate (or trifoliate)
a compound leaf of three leaflets, for example a clover leaf.
trigonous
triangular in cross-section and obtusely angled; cf. triquetrous.
trimerous
in three parts, particularly with respect to flowers, three parts in each whorl. See also tetramerous and pentamerous.
trinerved
having three nerves or veins.
triplinerved
(of leaves) having three main nerves with the lateral nerves arising from the midnerve above the base of the leaf.
triquetrous
more or less triangular in cross-section, but acutely angled (with 3 distinct longitudinal ridges); cf. trigonous.
trivalve
also trivalvar. Divided into three valves. See also bivalve
trivial name
the second word in the two-part scientific name of an organism; cf. specific epithet.
trophophyll
a vegetative, nutrient-producing leaf or microphyll, whose primary function is photosynthesis. It is not specialized or modified for some other function. (compare: sporophyll).
trullate
ovate but angled; like a bricklayer's trowel; inverse kite-shaped; compare rhombic.
truncate
cut off squarely; with an abruptly transverse end.
trunk
the upright large main stem of a tree.
truss
a compact cluster of flowers or fruits arising from one centre; for instance, evident in many rhododendrons.
tuber
an underground storage organ formed by the swelling of an underground stem which produces buds and stores food, forming a seasonal perennating organ, for example potato; compare tuberoid.
tubercle
a small wart-like outgrowth.
tuberculate
covered in tubercles; warty.
tuberoid
an underground storage organ formed by the swelling of a root; occurs in many orchids.
tuberous
resembling a tuber; producing tubers.
tubular
with the form of a tube or cylinder.
tufted
densely fasciculate at the tip.
tunic
outer covering of some bulbs and corms, hence tunicate.
tunicate
of bulbs, consisting of concentric coats.
turbinate
top-shaped.
turgid
swollen with liquid; firm; compare flaccid.
tussock
a dense tuft of vegetation, usually well separated from neighbouring tussocks, for example some grasses; compare sward.
two-ranked
having leaves arranged in two rows in the same plane, on opposite sides of the branch; = distichous.
type
an item (usually a herbarium specimen) to which the name of a taxon is permanently attached, i.e. a designated representative of a plant name. Important in determining the priority of names available for a particular taxon.
type genus
in nomenclature, the genus from which the family is based.
typography
the presentation of printed matter, covering issues such as type styles (e.g. italic or roman type), underlining, emboldening and letter spacing.

U

umbel
(adjective umbellate) a racemose inflorescence in which all the individual flower stalks arise in a cluster at the top of the peduncle and are of about equal length; in a simple umbel, each stalk is unbranched and bears only one flower; a cymose umbel looks similar to an umbel but its flowers open centrifugally.
Umbo in the middle of the cap of Cantharellula umbonata.
umbo (mycology)
a rounded elevation, such as in the middle of the top of an umbrella or mushroom
umbonate
having an umbo, with a conical or blunt projection arising from a flatter surface, as on the top of a mushroom, or in the scale of a pine cone.
unciform
hook shaped.
uncinate
with a hook at the apex.
undershrub
a low shrub, often with flowering branches that die off in winter; cf. subshrub.
understory
plant life growing beneath the forest canopy.
undulate
wavy and not flat; compare sinuate.
uniflor
having a single flower (uniflory). Compare pauciflor (few) and pluriflor (many)
unilocular
having one loculus or chamber, e.g., the ovary in the families Proteaceae and Fabaceae.
uniserial
Arranged in a single row or series. Unbranched. Uniseriate.
uniseriate
Arranged in a single row or series. Unbranched. Uniserial.
unisexual
of one sex; bearing only male or only female reproductive organs, dioecious, dioicous. See Sexual reproduction in plants.
unitegmic
(of an ovule), covered by a single integument.
urceolate
literally means "shaped like an urn" (or pitcher), with a swollen middle and narrowing top. Examples of urceolate plant structures are the pitchers of many species of the pitcher plant genera Sarracenia and Nepenthes. Etymology: Mid-18th century, From Latin urceolus "little pitcher", urceus "pitcher".
usu.
abbreviation for usually, compare s.t. and oft.
utricle
a small bladder; a membranous bladder-like sac enclosing an ovary or fruit; in sedges a fruit in which the pericarp is larger than, and loosely encloses, the seed.

V

vallecular canal
a resin canal coinciding with a longitudinal groove in the seeds of Asteraceae. A longitudinal cavity in the cortex of the stems of Equisetum, coinciding with a groove in the stem surface.
valvate
of sepals and petals in bud, which meet edge to edge but do not overlap.
valve
a portion of an organ that fragments or splits open, for example the teeth-like portions of a pericarp in a split (dehisced) capsule or pod when ripe.
var
see varietas.
variant
a plant or group of plants showing some measure of difference from the characteristics associated with a particular taxon.
varietas (variety in common usage, abbreviated as var.)
(Latin) in the Linnean hierarchy a rank below that of species, between the ranks of subspecies and form.
variegated
irregularly marked with blotches or patches of another colour.
vascular
an adjective referring to the conducting tissues, the (xylem and phloem), in vascular plants.
vascular bundle
a bundle of vascular tissue in the primary stems of vascular plants, consisting of specialised conducting cells for the transport of water (xylem) and assimilate (phloem).
vasculum
Container used by botanists for collecting field specimens.
vein
a strand of vascular tissue, e.g. in vascular plant leaves; nerve.
veinlet
a small vein; the ultimate (visible) division of a vein.
velamen
a spongy tissue covering the aerial roots of orchids and some other epiphytes.
velvety
densely covered with fine, short, soft, erect hairs.
venation
the arrangement of veins in a leaf.
ventral
the front; in particular, towards the axis (adaxial) in a lateral organ or towards the substrate in a prostrate plant; contrast dorsal, abaxial.
vernation
the arrangement of unexpanded leaves in a bud; the order of unfolding of leaves from a bud.
verruciform
wart-like in form.
verrucose
with warts.
verruculose
minutely warty, minutely verrucose.
versatile
of anthers, swinging freely about the point of attachment to the filament.
verticillate
arranged in one or more whorls, i.e. several similar parts arranged at the same point of the axis. e.g. leaf arrangement. Hence pseudoverticillate, appearing whorled or verticillate but not so
verticillaster
a type of pseudo-verticillate inflorescence, typical of Lamiaceae, in which pseudo-whorls are formed from pairs of opposite cymes.
vesicular
of hairs, bladder-like; vesciculous, bearing such hairs.
vessel
a capillary tube formed from a series of open-ended cells in the water-conducting tissue of a plant.
vestigial
reduced in form and function from the normal or ancestral condition.
villous
Abounding in or covered with long, soft, straight hairs; shaggy with soft hairs.
vine
1.  Vitis.
2.  Scandent plants climbing by means of trailing or twining stem or runner.
3.  Such a stem or runner[2][10]
virgate
Wand-shaped, twiggy, especially referring to erect, straight stems. Diminutive: virgulate. In mycology, referring to a pileus with radiating ribs or lines.
Viridiplantae
literally "green plants". A clade of autotrophic organisms that includes green algae, Charophyta and land plants, that have cellulose in their cell walls, chloroplasts derived from primary endosymbiosis with Cyanobacteria that contain chlorophylls a and b and lack phycobilins.
viscid
sticky; coated with a thick, syrupy secretion.
viviparous
1.  seeds or fruits which germinate before being shed from the parent plant.
2.  the development of plantlets on non-floral organs e.g. leaves.

W

Watershoots
warty
a surface covered with small round protuberances, especially in fruit, leaves, twigs and bark, see tuberculate.
watershoot
an erect strong-growing or epicormic shoot developing from near the base of a shrub or tree, but distinct from a sucker.
weed
1.  a weed is loosely defined as a plant growing where it is not wanted; commonly associated with disrupted habitats. See also ruderal
2.  agricultural weed: an unwanted plant which grows among agricultural crops.
3.  environmental weed: naturalised, exotic or ecologically 'out-of-balance' indigenous species outside the agricultural or garden context which, as a result of invasion, adversely affects the survival or regeneration of indigenous species in natural or partly natural vegetation communities (Carr, G.W., in Foreman & Walsh, 1993).
wild
originating from a known wild habitat (wilderness). See Wildlife.
whorl
a ring of organs borne at the same level on an axis, for example leaves, bracts or floral parts.
wing
1.  a membranous expansion of a fruit or seed which aids in dispersal, for instance on pine seeds.
2.  a thin flange of tissue extending beyond the normal outline of a structure, e.g. on the column of some orchids, on stems, on petioles.
3.  one of the two lateral petals of a flower of subfamily Faboideae of family Fabaceae, located between the adaxial standard (banner) petal and the two abaxial keel petals.
woolly
very densely covered with long, more or less matted or intertwined hairs, resembling sheep's wool.

X

xeromorph
a plant with structural features (e.g. hard or succulent leaves) or functional adaptations that prevent water loss by evaporation; usually associated with arid habitats, but not necessarily drought-tolerant; cf. xerophyte.
xerophyte
a plant generally living in a dry habitat, typically showing xeromorphic or succulent adaptation; a plant able to tolerate long periods of drought; cf. xeromorph.
xylem
a specialised water-conducting tissue in vascular plants.

Z

zonate
having light and dark circular bands or rings.
zygomorphic
bilaterally symmetrical; symmetrical about one vertical plane only; applies to flowers in which the perianth segments within each whorl vary in size and shape; compare actinomorphic, irregular.
zygote
a fertilized cell, the product of fusion of two gametes.

See also

References

  1. Shreve, Forrest; Wiggins, Ira. Vegetation and Flora of the Sonoran Desert. Stanford University Press, 1964. ISBN 978-0804701631
  2. 1 2 3 4 Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Derivation and Accent; Published by Gerald Duckworth & Co. London, 4th ed 1928
  3. 1 2 Jaeger, Edmund Carroll (1959). A source-book of biological names and terms. Springfield, Ill: Thomas. ISBN 0-398-06179-3.
  4. Mosses Lichens & Ferns of Northwest North America, Dale H. Vitt, Janet E. marsh, Robin B. Bovey, Lone Pine Publishing Company, ISBN 0-295-96666-1
  5. Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, ISBN 978-0-300-19500-2, page 279
  6. Alan W. Meerow, Michael F. Fay, Charles L Guy, Qin-Bao Li, Faridah Q Zaman, Mark W. Chase. Systematics of Amaryllidaceae based on cladistic analysis of plastid sequence data. Am. J. Bot. September 1999 vol. 86 no. 9 1325-1345
  7. THE SPLASH-CUP DISPERSAL MECHANISM IN PLANTS, Harold J. Brodie, Canadian Journal of Botany, 1951, 29(3): 224-234, 10.1139/b51-022,
  8.  Beach, Chandler B., ed. (1914). "Tetrad". The New Student's Reference Work. Chicago: F. E. Compton and Co.
  9.  Beach, Chandler B., ed. (1914). "Tetraspore". The New Student's Reference Work. Chicago: F. E. Compton and Co.
  10. Brown, Lesley (1993). The New shorter Oxford English dictionary on historical principles. Oxford [Eng.]: Clarendon. ISBN 0-19-861271-0.

Bibliography

Royal Botanical Gardens at Kew

Australia and New Zealand

Africa


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