Penstemon

Penstemon
balloon flower (Penstemon palmeri)
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Lamiales
Family: Plantaginaceae
Genus: Penstemon
Schmidel, 1763
Species

See text.

Penstemon /ˈpɛnstmən/,[1] the beardtongues, is a large genus of roughly 250 species North American and East Asian flowering plants. Formerly placed in the Scrophulariaceae family by the Cronquist system, new genetic research has placed it in the vastly expanded Plantaginaceae family.

A prominent, often hairy, staminode is the most distinctive feature of this genus, as in this Penstemon rupicola flower
Golden-beard Penstemon (Penstemon barbatus)
Penstemon bridgesii
Bellflower Beardtongue (Penstemon campanulatus)
Penstemon confertus
Talus Slope Penstemon (Penstemon digitalis)
Lowbush Penstemon (Penstemon fruticosus)
Davidson's Penstemon (Penstemon davidsonii)
Lilac Penstemon (Penstemon gracilis)
Hairy Beardtongue (Penstemon hirsutus)
Penstemon hirsutus pubescens
Pineneedle Beardtongue (Penstemon pinifolius)
Littleflower Penstemon (Penstemon procerus)
Serrulate Penstemon (Penstemon serrulatus)
Prairie-clover (Penstemon speciosus)

They have opposite leaves, partly tube-shaped, and two-lipped flowers and seed capsules. The most distinctive feature of the genus is the prominent staminode, an infertile stamen. The staminode takes a variety of forms in the different species; while typically a long straight filament extending to the mouth of the corolla, some are longer and extremely hairy, giving the general appearance of an open mouth with a fuzzy tongue protruding and inspiring the common name beardtongue.

Most penstemons are deciduous or semi-evergreen perennials, the remainder being shrubs or subshrubs. Heights can range from 10 cm to as much as 3 metres.

The one Asiatic species previously treated in Penstemon is now placed in a separate genus Pennellianthus. This leaves Penstemon a mostly nearctic genus, with a few neotropical species. Although widespread across North America, and found in habitats ranging from open desert to moist forests, and up to the alpine zone, they are not typically common within their range.

History

John Mitchell published the first scientific description in 1748; although he only named it as Penstemon, we can identify it as P. laevigatus. Linnaeus then included it in his 1753 publication, as Chelone pentstemon, altering the spelling to better correspond to the notion that the name referred to the unusual fifth stamen (Greek "penta-", five). Mitchell's work was reprinted in 1769, continuing with his original spelling, and this was ultimately accepted as the official form, although Pentstemon continued in use into the 20th century.

Although several more species were found in the 18th century, they continued to be classified in Chelone until about the 1820s. The period of 1810 to 1850 increased the number of known species from 4 to 63, as expeditions traveled through Mexico and the western United States, followed by another 100 up to 1900.

During this time, seeds began to be offered for sale in Europe, the earliest known dating from 1813, with John Fraser offering four species in London, followed by Flanagan & Nutting offering nine species in their 1835 catalog. Subsequently many hybrids were developed in Europe.

Fieldwork in the remote parts of the Great Basin during the 20th century brought the total number of species known to over 250. The genus was extensively revised by David Keck between 1932 and 1957; in 1946 the American Penstemon Society was formed to promote both horticultural and botanical interest.

Uses

Some Native American tribes used penstemons as medicinal remedies for humans and animals.[2] Today its primary use is ornamental.

Horticulture

Although penstemons are among the most attractive native flowers of North America, Europe has traditionally been far more active in their hybridization with hundreds of hybrids developed since the early 19th century. The earliest development is somewhat shrouded in mystery; for instance Flanagan & Nutting's 1835 catalog mentions a 'Penstemon Hybridum' but does not describe it.

By 1860, a half-dozen French growers are known to have developed hybrids, most notably Victor Lemoine, while in 1857 the German Wilhelm Pfitzer listed 24 varieties. In 1861 the Royal Horticultural Society held trials in which 78 varieties were entered. The Scottish firm of John Forbes first offered penstemons in 1870, eventually becoming the biggest grower in the world; in 1884 their catalog listed 180 varieties. By 1900 Forbes had offered 550 varieties, while Lemoine had developed nearly 470 by the time of his death in 1911. Few of these have survived to the present day.

A number of different species have been used in the hybridization process, notably P. cobaeus and P. hartwegii.

In North America, penstemons are often used in xeriscape landscaping, as many are native to desert or alpine regions and thus quite hardy. One of the largest collections of penstemons in North America is found at The Arboretum at Flagstaff, Arizona, which hosts a Penstemon Festival each summer.[3]

The following cultivars have gained the Royal Horticultural Society's Award of Garden Merit:-

'Alice Hindley'[4] P. isophyllus[5]
'Andenken an Friedrich Hahn'[6] 'Margery Fish'[7]
'Apple Blossom'[8] 'Maurice Gibbs'[9]
'Beech Park'[10]'Osprey'[11]
'Cherry'[12] 'Pennington Gem'[13]
'Chester Scarlet'[14] 'Port Wine'[15]
'Connie's Pink'[16] 'Roy Davidson'[17]
'Evelyn'[18] 'Raven'[19]
'George Home'[20] 'Rubicundus'[21]
P. hartwegii[22] 'Schoenholzeri'[23]
'Catherine de la Mare'[24]'Sour Grapes'[25]
'Hewell Pink Bedder'[26]'Stapleford Gem'[27]
'Hidcote Pink'[28] 'White Bedder'[29]

Others include 'Dark Towers', developed by Dale Lindgren at the University of Nebraska. [30]

Species

References

Notations

Footnotes

  1. Sunset Western Garden Book, 1995:606–607
  2. Escamilla, G., et al. Penstemon ambiguus. Medicinal Plants of the Southwest. New Mexico State University. 2001. Updated 2008.
  3. "Penstemon Festival". Thearb.org. Retrieved 2012-08-04.
  4. "RHS Plant Selector Penstemon 'Alice Hindley' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  5. "RHS Plant Selector Penstemon isophyllus AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  6. "RHS Plant Selector Penstemon 'Andenken an Friedrich Hahn' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  7. "RHS Plant Selector Penstemon 'Margery Fish' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  8. "RHS Plant Selector Penstemon 'Apple Blossom' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  9. "RHS Plant Selector Penstemon 'Maurice Gibbs' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  10. "RHS Plant Selector Penstemon 'Beech Park' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  11. "RHS Plant Selector Penstemon 'Osprey' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  12. "RHS Plant Selector Penstemon 'Cherry' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  13. "RHS Plant Selector Penstemon 'Pennington Gem' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  14. "RHS Plant Selector Penstemon 'Chester Scarlet' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  15. "RHS Plant Selector Penstemon 'Port Wine' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  16. "RHS Plant Selector Penstemon 'Connie's Pink' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  17. "RHS Plant Selector Penstemon procerus 'Roy Davidson' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  18. "RHS Plant Selector Penstemon 'Evelyn' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  19. "RHS Plant Selector Penstemon 'Raven' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  20. "RHS Plant Selector Penstemon 'George Home' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  21. "RHS Plant Selector Penstemon 'Rubicundus' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  22. "RHS Plant Selector Penstemon hartwegii AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  23. "RHS Plant Selector Penstemon 'Schoenholzeri' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  24. "RHS Plant Selector Penstemon heterophyllus 'Catherine de la Mare' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  25. "RHS Plant Selector Penstemon 'Sour Grapes' M. Fish AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  26. "RHS Plant Selector Penstemon 'Hewell Pink Bedder' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  27. "RHS Plant Selector Penstemon 'Stapleford Gem' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  28. "RHS Plant Selector Penstemon 'Hidcote Pink' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  29. "RHS Plant Selector Penstemon 'White Bedder' AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-08-04.
  30. Walters Gardens. Penstemon 'Dark Towers' PP20013
  31. Francis Whittier PennellThe Scrophulariaceae of Eastern Temperate North America, p. 270, at Google Books
  32. Turner, B. L. (2010). Taxonomy of the Penstemon campanulatus complex (Scrophulariaceae) and description of a new species from its midst. Phytoneuron 31 1–5.
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