Penstemon caespitosus

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Penstemon caespitosus
Penstemon caespitosum - Flickr - aspidoscelis (2).jpg
Penstemon caespitosus in Cochetopa Canyon, southeast of Gunnison, Colorado, and north of Iris, Colorado
Status TNC G5.svg
Secure  (NatureServe)
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Lamiales
Family: Plantaginaceae
Genus: Penstemon
Species:
P. caespitosus
Binomial name
Penstemon caespitosus
Varieties [1]
  • Penstemon caespitosus var. caespitosus
  • Penstemon caespitosus var. desertipicti (A.Nelson) N.H.Holmgren
  • Penstemon caespitosus var. perbrevis (Pennell) N.H.Holmgren

Penstemon caespitosus, commonly known as mat penstemon, is a summer blooming perennial flower in the large Penstemon genus. It is a widespread plant from near timberline to the foothills in the Southern Rocky Mountains and Colorado Plateau in North America. It is noted for its ground hugging growth habit and as a plant used in xeriscape and rock gardening.

Contents

Description

Penstemon caespitosus, photo taken 10 miles north of Vernal, Utah 2017.06.05 09.07.11 IMG 0427 - Flickr - andrey zharkikh.jpg
Penstemon caespitosus, photo taken 10 miles north of Vernal, Utah

Penstemon caespitosus is very low growing, usually just 4–5 centimeters (1.6–2.0 in) tall with the stems laying down and only the tips curving upright. [2] [3] Most often individual stems are 2–8 centimeters (0.79–3.15 in) in length, but occasionally will be 10 centimeters (3.9 in) long. [4] Older stems will be woody and have many branches. The stems root at nodes eventually forming solid mat up to 2 meters (6 ft 7 in) in width. [3] [5] The stems have small backwards pointing (retrorse) hairs giving the stems a rough texture, but not giving them an ashy appearance. [4]

The leaves of Penstemon caespitosus are attached by a short leaf stem to the main stems, rather than to the base of the plant, each stem having 3–20 pairs of leaves. Like the stems they are covered in pointed backwards facing hairs, but they do not hide the green color of the leaves. The leaves are variable in shape from being wider at the end than at the base (blade obovate to spatulate) or fairly narrow and grass like (linear) with a tapered base. Their size range from 2.5-14 millimeters long and 1–4 millimeters wide, though occasionally they may be a long as 21 millimeters. The tips of their leaves can be rounded, narrowly pointed, or even have the leaf's main rib sticking out to form a sharp tip (mucronate). [4]

Penstemon caespitosus, dissected flower 2017.06.09 21.22.33 IMG 0657 - Flickr - andrey zharkikh.jpg
Penstemon caespitosus, dissected flower

The flowering season is as early as April and as late as July or August. [2] [6] The flowers are a variant on the classic penstemon structure of the petals being united into a tube, in this case with five narrow lobes with rounded ends, 4–6.5 mm in length and 1–1.5 mm wide. [4] Overall the flowers are 10–17 millimeters long, though in exceptional cases they may be as long as 21 millimeters with a funnel to bell shape to the tube. [3] As with the leaves and stems they flowers are retrorsely hairy, though they also will have sparse glandular hairs. The externally the flowers are a handsome blue to purplish lavender with reddish violet nectar guides on the petal lobes into the interior. On the lower surface of the flower tube there will be two ridges. [4] The interior of the flower tube is more white-ish in color [3] with the 5–6 millimeter long tube lined with villous hairs. [4] Each flower has four stamens, the longer two stamens will reach or extend slightly beyond the opening of the flower tube. The pollen sacs at the end of the stamens are 0.6–1.2 millimeters in diameter. The hairy staminode for which Penstemon are known 9–12 millimeters long and covered at the end with densely pilose bright golden yellow hairs. The female style is 13–15 millimeters long. [4]

The four lobed seed capsules are relatively small, 3.5–5 mm long by 3–4 mm wide. [4] One widely recognized species, Penstemon crandallii , is similar enough to Penstemon caespitosus to be confused with it. [3]

Taxonomy

The first recorded scientific collection of Penstemon caespitosus was by Thomas Nuttall and is assumed to have been on his expedition to Oregon in 1834. [3] It was named and more completely described by Asa Gray in 1862, but with the then common "correction" to the genus name to Pentstemon. [1] It had also been collected by John C. Frémont during one of his expeditions, but the condition of the specimen when examined by Gray was, "poor". [7] Botanist William A. Weber thought that Penstemon crandallii and its varieties not distinct enough to qualify as species and that it should be synonymized with P. caespitosus. [8] Two subspecies of P. caepitosus have been identified and are recognized by Plants of the World Online (POWO), the USDA Natural Resources Conservation Service PLANTS database (PLANTS), and the Flora of North America (FNA) as of 2023. [1] [9] [4]

Penstemon caespitosus var. caespitosus is the nominate subspecies. Compared to the others it more consistently has stems that turn upwards at the end compared to var. perbrevis and has smaller flowers than var. desertipicti. [5] [10] The main differences recorded in the FNA are the leaves are sometimes linear and the pollen sacs are explanate. However, sometimes the leaves of this variety are blade oblanceolate, similar or identical to the other varieties. [11] This variety's range overlaps with var. perbrevis, but does not with var. desertipicti and is recorded by both POWO and PLANTS as growing in Colorado, Utah, and Wyoming. [12] [13]

Penstemon caespitosus var. desertipicti was first described by Aven Nelson in 1926 as a separate species, Penstemon desertipicti and then as a subspecies by David D. Keck in 1937. [5] However, a more complete and accurate description was published by Noel H. Holmgren in 1979. [14] The physical characteristic noted by Keck as distinguishing it from var. caespitosus is having much broader flower tubes. [5] In FNA the primary differences recorded are only having blade oblanceolate leaves and never linear, blade obovate, or spatulate leaves as well as having navicular pollen sacs. [15] In 2011 it was found that this variety is 4n, a tetraploid. [16] Both POWO and PLANTS record this variety of P. caespitosus as growing in Utah and Arizona and being absent from the Rocky Mountains, this geographic isolation also being an argument for being a separate subspecies despite physical similarity. [3] [14] [17]

Penstemon caespitosus var. perbrevis was first described as a subspecies in 1920 by Francis W. Pennell. [10] As with var. desertipicti it was more completely and accurately described by Noel H. Holmgren in 1979. [18] Pennell described the difference from var. caespitosus as being mainly in that the stems do not turn upwards at the ends, but also that it has leaves that are wider at the ends with a longer and narrower base (spatulate). [10] In this the FNA is in agreement, recording the leaves as ranging in shape from blade obovate to spatulate. In addition describes the variety as having navicular to subexplanate pollen sacs in contrast to the other varieties. [19] Both POWO and PLANTS record this variety of P. caespitosus as growing in Utah and Colorado, with PLANTS specifically recording places of overlap in range in Utah and not having specific location information about the subspecies in Colorado. [18] [20]

Habitat and distribution

Penstemon caespitosus habitat in Wyoming, Long Creek Mountain Long Creek Mountain.jpg
Penstemon caespitosus habitat in Wyoming, Long Creek Mountain

Penstemon caespitosus grows in sagebrush scrublands, juniper savannas, openings in pinyon-juniper woodlands, with scrub oak, ponderosa pine woodlands, forb-grass openings in aspen-conifer communities, and in alpine meadows. Their altitude range is from as low as 1,500 meters (4,900 ft) to as high as 3,500 meters (11,500 ft). [2] [3]

Both POWO and PLANTS record Penstemon caespitosus in four western US states, Arizona, Colorado, Utah, and Wyoming. [1] [9] Most of the populations in Colorado and Wyoming are located west of the continental divide, but with a few populations found to the east. [3] NatureServe assessed P. caespitosus as globally secure (G5) in 1984. At the state level they assess populations in Colorado as apparently secure (S4), Wyoming populations as imperiled (S2), and Utah as critically imperiled (S1). [21]

Ecology

The specialist bee Osmia brevis , which is an oligolege that only visits Penstemon flowers, was observed visiting Penstemon caespitosus by A.L. McMullen. [22] Penstemon caespitosa is considered important for supporting the pollinators of the rare species Penstemon debilis by United States Fish and Wildlife Service. [23]

Cultivation

Mat penstemon is amenable to cultivation and is widely grown in both Europe and America as a groundcover especially in rock gardens for xeriscaping. [24] It is recommended by the Royal Horticultural Society for planting in crevice gardens. [25] In comparison to Penstemon thompsoniae and Penstemon teucrioides , it is less sensitive to moisture because it evolved to live in less extreme environments in the Rockies. [26] Though more tolerant of moisture than other mat forming species it is, like most penstemons, susceptible to root rot in poorly draining locations. It is especially intolerant of excess moisture immediately after its blooming period. [27] However, it will grow on clay containing soils in dry conditions and is generally healthier on lean soils low in organic matter. [28] [2] [27] They are quite suitable for a rock garden, but are too vigorously spreading for trough planting with other plants. [26] The seeds of mat penstemon were experimentally germinated using gibberellic acid sprinkled over seeds on wet paper towels at a dosage of approximately 1000 ppm and this resulted in 30% germination after six weeks while there was no germination from cold treatment alone. [29]

A number of named cultivars of the mat penstemon are available in the horticultural trade. 'Claude Barr', also sometimes called 'Denver Botanical Gardens' is a form with smaller rounded leaves. 'Bruce Alexander' is a cultivar with white flowers and yellow-green leaves. [26] 'Waggon wheel' introduced in 2022 by the Plant Select cooperative sponsored by Colorado State University and Denver Botanic Gardens. [30] Mat penstemon is hardy in USDA zones 4–7. [28] [31]

See also

List of Penstemon species

Related Research Articles

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<i>Liatris chapmanii</i> Species of flowering plant

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<i>Penstemon anguineus</i> Plant species in the plantain family

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<i>Penstemon barnebyi</i> Plant species in the plantain family

Penstemon barnebyi is a species of penstemon known by the common names White River Valley beardtongue and Barneby's beardtongue. It is native to the mountain and basin territory of central western Nevada, where it grows in sagebrush and woodland; there is also one occurrence just over the California border.

<i>Penstemon thompsoniae</i> Species of shrub

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<i>Penstemon grandiflorus</i> Species of flowering plant in the family Plantaginaceae

Penstemon grandiflorus, known by the common names shell-leaved penstemon, shell-leaf beardtongue, or large-flowered penstemon, is a tall and showy plant in the Penstemon genus from the plains of North America. Due to its large flowers it has found a place in gardens, particularly ones aimed at low water usage like xeriscape gardens.

<i>Penstemon angustifolius</i> Plant species in the plantain family

Penstemon angustifolius is a perennial semi-evergreen forb belonging to the plantain family. This species is 1 out of roughly 273 species of Penstemon. This species is also known as broadbeard beardtongue. This forb is native to central United States and can be noticed by its brightly and highly variable colored flowers.

<i>Symphyotrichum falcatum</i> Species of flowering plant in family Asteraceae

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<i>Castilleja integra</i> Species of flowering plant

Castilleja integra, with the common names orange paintbrush, Southwestern paintbrush, and wholeleaf paintbrush, is a partially parasitic herbaceous perennial plant native to the Southwestern United States and Northern Mexico. The species produces a relatively large amount of nectar and is attractive to hummingbirds. It is better suited to cultivation than most other species in the paintbrush genus (Castilleja) and is therefor used in xeriscape gardens and naturalistic meadows, even outside its native range.

<i>Urtica gracilis</i> Species of flowering plant

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<i>Penstemon whippleanus</i> Species of flowering plant

Penstemon whippleanus, commonly known as dusky penstemon, dusky beardtongue, Whipple's penstemon, or Whipple's beardtongue, is a summer blooming perennial flower in the large Penstemon genus. It is a widespread plant within the hemiboreal forests of the Rocky Mountains in North America. It is noted for the large deep purple-red flowers and a preference for high mountain elevations.

<i>Penstemon virens</i> Species of flowering plant

Penstemon virens, commonly known as blue mist penstemon, Front Range penstemon, or Green beardtongue, is a common Penstemon in the Front Range foothills in Colorado and Wyoming. The dainty flowers are an ornament to many rocky or sandy area within its range. It is confusingly similar to Penstemon humilis and Penstemon albertinus though the ranges of these plants do not overlap in the wild. The origin of calling it the "blue mist penstemon" is not precisely known, but is thought to relate to the large number of blue flowers the plant can produce reminding observers of a blue mist.

<i>Penstemon albidus</i> Species of flowering plant

Penstemon albidus, commonly known as white penstemon, white-flower beardtongue, or Red-Line Beardtongue is a very widespread perennial flower of the mixed-grass and shortgrass prairies. Its natural distribution is from Manitoba and Alberta in Canada to Texas and New Mexico in the United States. The bright white flowers for which they are named are quite attractive to both bees and hummingbird moths.

<i>Penstemon secundiflorus</i> Species of flowering plant

Penstemon secundiflorus, commonly known as sidebells penstemon, or orchid beardtoungue is a species of Penstemon that grows in dry forests, high plains, and scrub lands from Wyoming to Mexico. It is a herbaceous perennial plant that typically grows to a height of 20 to 50 cm and has narrow, lance-shaped leaves that are grayish-green in color. The flowers of the sidebells penstemon are tubular in shape and are arranged in a one-sided spike, with the blooms all facing the same direction, and for this reason was named "secundiflorus", which means "one-sided flowers". The flowers are most often delicate shades of orchid or lavender. It is sometimes used in xeriscaping, rock gardens, and wildflower meadows, and is well-suited to dry, sunny locations with well-draining soil.

<i>Penstemon ambiguus</i> Species of flowering plant

Penstemon ambiguus, commonly known as the bush penstemon, pink plains penstemon, or gilia beardtongue is a species of Penstemon that grows in the shortgrass prairies and deserts of the western United States and northern Mexico. This bush-like penstemon grows in sandy, loose, and creosote soils and is particularly known for the spectacular flowering show it produces, sometime seasons turning whole hillsides bright pink–white.

<i>Penstemon auriberbis</i> Species of flowering plant

Penstemon auriberbis, commonly known as the Colorado penstemon or Colorado beardtongue, is a species of Penstemon that grows in the shortgrass prairies of southern Colorado and in a few places in northern New Mexico. Although specimens were collected on the 1820 expedition by Stephen H. Long through the area, they were not scientifically described as a separate species until 1920.

<i>Lupinus caudatus</i> Species of flowering plant in the family Fabaceae

Lupinus caudatus is a widespread species of wildflower in genus Lupinus from western North America known by the common names tailcup lupin and spurred lupin. It is distinctive for the short spur on its purple-blue flowers, for which it is named. Because of its wide distribution and toxicity it commonly causes poisonings of susceptible livestock such as horses, cattle, and sheep, though it is eaten without harm by wild herbivores like deer and elk. It is generally found from the Coastal Ranges and Sierra Nevada Mountains in the west to the Rocky Mountains in the east.

<i>Noccaea fendleri</i> Western North American species of flowering plant in the cabbage family

Noccaea fendleri more commonly known as wild candytuft and alpine pennycress is a wildflower in the mustard family from western North America. It grows in mountains from northern Mexico to the northern United States. It blooms early in the spring and provides nectar to butterflies.

<i>Penstemon albifluvis</i> Plant species in the plantain family

Penstemon albifluvis, the White River penstemon, is a disputed species or variety of Penstemon that grows in a small area in eastern Utah and western Colorado. It grows mainly on broken shale and rock formations in desert habitats. White River penstemon is very rare.

References

  1. 1 2 3 4 POWO (2023). "Penstemon caespitosus Nutt. ex A.Gray". Plants of the World Online . Royal Botanic Gardens, Kew . Retrieved 12 May 2023.
  2. 1 2 3 4 "Penstemon caespitosus var. caespitosus". Wolfe Lab. Ohio State University. 2014. Retrieved 18 May 2023.
  3. 1 2 3 4 5 6 7 8 9 Barnett, Don; Barnett, Donnie (2022). Penstemon of Southeastern Colorado. Pueblo, CO: Ethical Desert. pp. 94–99. ISBN   978-0-578-37397-3.
  4. 1 2 3 4 5 6 7 8 9 Freeman, Craig C. (6 November 2020). "Penstemon caespitosus - FNA". Flora of North America. Retrieved 23 May 2023.
  5. 1 2 3 4 Keck, David D. (1937). "Studies in Penstemon IV. The section Ericopsis". Bulletin of the Torrey Botanical Club. 64 (6): 359, 363–364. doi:10.2307/2481121. JSTOR   2481121 . Retrieved 19 May 2023.
  6. ↑ Ackerfield, Jennifer (2015). Flora of Colorado (1 ed.). Fort Worth: BRIT press. p. 590. ISBN   978-1-889878-45-4.
  7. ↑ Gray, Asa (May 1862). "Synopsis of the Genus Pentstemon". Proceedings of the American Academy of Arts and Sciences. 6. MIT Press. Retrieved 18 May 2023.
  8. ↑ Weber, William A.; Wittmann, Ronald C. (2012). Colorado Flora: Eastern Slope, Fourth Edition A Field Guide to the Vascular Plants. University Press of Colorado. ISBN   978-1607321408.
  9. 1 2 USDA, NRCS (2023). "​Penstemon caespitosus Nutt. ex A. Gray​". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 18 May 2023.
  10. 1 2 3 Pennell, Francis W. (1917). "Scrophulariaceae of the Central Rocky Mountain States". Contributions from the United States National Herbarium. 20 (9). Smithsonian Institution Press: 335, 375. Retrieved 22 May 2023.
  11. ↑ Freeman, Craig C. (5 November 2020). "Penstemon caespitosus var. caespitosus - FNA". Flora of North America. Retrieved 23 May 2023.
  12. ↑ POWO (2023). "Penstemon caespitosus var. caespitosus". Plants of the World Online . Royal Botanic Gardens, Kew . Retrieved 22 May 2023.
  13. ↑ USDA, NRCS (2023). "​Penstemon caespitosus Nutt. ex A. Gray var. caespitosus​". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 22 May 2023.
  14. 1 2 POWO (2023). "Penstemon caespitosus var. desertipicti (A.Nelson) N.H.Holmgren". Plants of the World Online . Royal Botanic Gardens, Kew . Retrieved 19 May 2023.
  15. ↑ Freeman, Craig C. (5 November 2020). "Penstemon caespitosus var. desertipicti - FNA". Flora of North America. Retrieved 23 May 2023.
  16. ↑ Broderick, Shaun R.; Stevens, Mikel R.; Geary, Brad; Love, Stephen L.; Jellen, Eric N.; Dockter, Rhyan B.; Daley, Shawna L.; Lindgren, Dale T. (February 2011). "A survey of Penstemon's genome size". Genome. 54 (2): 160–173. doi:10.1139/G10-106. PMID   21326372 . Retrieved 19 May 2023.
  17. ↑ USDA, NRCS (2023). "​Penstemon caespitosus Nutt. ex A. Gray var. desertipicti (A. Nelson) N.H. Holmgren​". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 22 May 2023.
  18. 1 2 POWO (2023). "Penstemon caespitosus var. perbrevis (Pennell) N.H.Holmgren". Plants of the World Online . Royal Botanic Gardens, Kew . Retrieved 22 May 2023.
  19. ↑ Freeman, Craig C. (5 November 2020). "Penstemon caespitosus var. perbrevis - FNA". Flora of North America. Retrieved 23 May 2023.
  20. ↑ USDA, NRCS (2023). "​Penstemon caespitosus Nutt. ex A. Gray var. perbrevis (Pennell) N.H. Holmgren​". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 22 May 2023.
  21. ↑ NatureServe (2023). "Penstemon caespitosus". NatureServe Explorer. Arlington, Virginia: NatureServe. Retrieved 27 May 2023.
  22. ↑ Tepedino, V.J.; Griswold, T.L.; Freilich, J.E.; Shephard, P. (December 2011). "Specialist and Generalist Bee Visitors of an Endemic Beardtongue ( Penstemon caryi: Plantaginaceae) of the Big Horn Mountains, Wyoming". Western North American Naturalist. 71 (4): 527. doi:10.3398/064.071.0410. S2CID   56266655 . Retrieved 26 May 2023.
  23. ↑ 77 FR 48368
  24. ↑ Shonle, I.; Vickerman, L.G.; Klett, J.E. (April 2014). "Native Herbaceous Perennials for Colorado Landscapes - 7.242". Colorado State Extension. Colorado State University. Retrieved 25 May 2023.
  25. ↑ "RHS Advice". Garden. 139 (7). Royal Horticultural Society: 28. July 2014.
  26. 1 2 3 Way, David; James, Peter (1998). The gardener's guide to growing penstemons. N: David & Charles. pp. 29, 85. ISBN   978-0-88192-424-4.
  27. 1 2 "Penstemon caespitosus - mat penstemon". Garden Explorer. Santa Fe Botanical Garden. 2023. Retrieved 25 May 2023.
  28. 1 2 "Penstemon caespitosus". Missouri Botanical Garden Plant Finder. Missouri Botanical Garden. Retrieved 19 May 2023.
  29. ↑ Love, Stephen L; Akins, Candace J (2020). "Fifth summary of the native seed germination studies of Norman C Deno: species with names beginning with letters P and Q". Native Plants Journal. 21 (1): 88. doi:10.3368/npj.21.1.83. S2CID   241374952.
  30. ↑ Langelo, Linda (18 January 2022). "Plant Select 2022 New Introductions". Morning Ag Clips. Retrieved 19 May 2023.
  31. ↑ Kelsey, Amber (21 September 2017). "Penstemon Plant List". Garden Guides. Retrieved 25 May 2023.
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