Penstemon virens
Penstemon virens

Vulnerable  (NatureServe)
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Lamiales
Family: Plantaginaceae
Genus: Penstemon
Species:
P. virens
Binomial name
Penstemon virens

Penstemon virens, commonly known as blue mist penstemon,[1] Front Range beardtongue,[2] or Green beardtongue,[3] 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.[4] The common name, blue mist penstemon, refers to the cloud of flowers on multiple stems facing every direction.[5]

Description

Penstemon Virens growing from a rockface, Clear Creek County.

Penstemon virens has flowering stems are typically 10–40 cm in height and stand upright with very little curve.[3] The stems are covered in extremely fine and short hairs that increase to being glandular and hairy closer to the buds and flowers, but are rarely almost or completely hairless.[6]

Most of the leaves are at the base of the plant and relatively short, 2–10.2 cm long.[3] These basal leaves are bright green, smooth, shiny, and have smooth or very finely toothed edges (denticulate margins).[4] Though smooth, the leaves are not leathery or thick, and are oblanceolate to spatulate with a tapered base and 4–15 mm in width.[3] The end of the leaves are mildly pointed, ranging from obtuse to acute.[6] The leaves attached to the flowering stems are also hairless, have smooth leaf edges, lancelolate to slightly ovate in shape, and shorter than the basal leaves, 1.8–5 cm in length and 3–14 mm wide.[3] The form of the plant is a low, spreading mat that enlarges each year,[5] with leaves that persist over the winter in most locations.[7]

The flowering stem is a thyrse, it grows without a genetically determined limit, but instead stops due to environmental conditions. It will typically have 3-6 clusters of flowers on the stem just above each leaf pair. Close examination will show that the flower clusters are actually paired groups on opposite sides of the stem (a verticillaster), but they will face in every direction. The flowers of Penstemon virens have five green, glandular-pubescent sepals at the base of the flower that are ovate to lanceolate, 2–4.5 mm long and 1.5-2.5 mm wide at the base.[3] The edge of each sepal is edged with red. The flower is a tapered funnel 10–16 mm long and pale sky blue to light purple or violet. The flower divides into five rounded petals at its front and has purple-blue to reddish-purple nectar guides from the center of each petal leading down into the flower. The outside of the flower is glandular-pubescent and on the inside has moderate amount of fine white fuzz on the inside of the flower. The throat of the flower tube has an inside diameter of 3–5 mm, about 4–5 mm on the outside.[6]

The lower lip and just inside the tube will have a few white longer hairs. The infertile fifth stamen, the staminode for which the genus is named, is a hairy golden-brown, and 8–10 mm long. It will almost reach the end of the flower tube. The four fertile stamens are paired above, curve inwards and upwards, and are purple to pink-white. The style is 8–11 mm long.[6]

The seed capsules are small tear drop shapes about 5–7 mm long and 2–3 mm wide[6] and are ripe towards the end of July or the beginning of August at lower elevations.[8]

Taxonomy

Herbarium specimen, collected near Laramie, Wyoming

The first recorded collection of Penstemon virens was by Francis W. Pennell on 9 June 1915 on Ute Creek north of Manitou Springs, CO. On the same trip he collected at least two more specimens from Colorado and two from locations in Wyoming, with the type specimen collected 13 June on a hillside west of Morrison, CO.[9][5] The famous Swedish-American botanist Per Axel Rydberg published a description that credited Pennell for the description in his book Flora of the Rocky Mountains and Adjacent Plains in 1917.[10] However, Rydberg is now credited with making formal description.[11] The name of the species, "virens', is the present active participle of the Latin word vireō (“I am green”).[12]

Habitat and distribution

Penstemon virens is commonly found growing on rocky slopes, on rock outcrops, in forest openings, along road cuts, and other disturbed areas.[4] They grow from 1600 to 3000 m in elevation.[13]

Penstemon virens is common in its habitat, but not widely distributed. Plants are found on the Medicine Bow Range in southeastern Wyoming south to Culebra Range in southeastern Colorado. It is common in the mountains and foothills of the Front Range in between and also on the Palmer Divide in Colorado.[13] It is recorded by the USDA Natural Resources Conservation Service PLANTS database (PLANTS) with county level records in Colorado and Wyoming.[2] NatureServe assessed P. virens as globally vulnerable (G3) in 1993. At the state level they did not assess populations in Colorado and evaluated Wyoming populations as "imperiled" (S2).[14]

Ecology

Penstemon virens tend to grow together in large numbers rather than singly or scattered throughout the landscape, rarely fewer than 10 plants in a population.[5] Most species observed visiting and entering the flowers of P. virens are bees. The most frequent visitors are members of genus Lasioglossum, but genus Osmia, genus Bombus, and honeybees also frequently visit them. Specific species observed include Apis mellifera, Augochlorella aurata, Bombus huntii, Bombus rufocinctus, Bombus centralis, Halictus tripartitus, Hoplitis truncata, Lasioglossum sisymbrii, and Lasioglossum trizonatum. They are also sometimes visited by beeflies (Bombyliidae) and butterflies, but they have not been observed contacting reproductive parts and are thought to be necatar robbers. Hummingbirds, though present in the range, have not yet been scientifically observed visiting P. virens.[15]

A study of plant responses to wildfire found that Penstemon virens was found in similar number of areas before and after five years of recovery from fires.[16] Though it does recover from fires an earlier study found that P. virens is significantly associated with areas of historic low-intensity fires in ponderosa pine forests.[17]

Penstemon virens was evaluated as a potential host for Castilleja integra and was found by the researchers to not support this partially parasitic plant for more than a few weeks.[18]

Cultivation

Blue mist penstemons are recommended as garden plants by local governments,[19] water providers,[20] and extension services[21] for areas in or near the Front Range. They are prized for their low water usage, adaptation to local climate, handsome blooms, long lifespan, and ease of cultivation.[7] They are drought tolerant once established, but not adapted to constantly dry conditions.[21]

In garden settings they are adapted to full sun to partial shade conditions in the west and full sun in the east of the United States.[7][22] They are quite adaptable to different garden soil conditions, but like all penstemons are healthier with good drainage.[7] Dr. Dale Lindgren of the University of Nebraska writes that their seeds require cold and moist stratification of six weeks at 4.5 °C for good germination rates or to be planted outside over the winter.[7] However, experiments by Dr. Norman C. Deno indicate that period of dry warm storage of around 21 °C (70 °F) for six months before cool moist stratification is critical. His research also showed that seeds left in the dry stems after ripening accomplish the same effect in natural settings.[23] The coldest USDA hardiness zones where this plant is known to survive is zone 4.[8]

References

  1. ↑ "blue-mist-penstemon". Colorado State Forest Service. Colorado State University. Retrieved 26 January 2023.
  2. 1 2 USDA, NRCS. (2023). "Penstemon virens Pennell ex Rydb". The PLANTS Database. Greensboro, NC USA.: National Plant Data Team. Retrieved 26 January 2023.
  3. 1 2 3 4 5 6 Ackerfield, Jennifer (2015). Flora of Colorado (First ed.). Fort Worth, Texas: Botanical Research Institute of Texas Press. p. 596. ISBN 9781889878454.
  4. 1 2 3 Denver Botanic Gardens (2018). Wildflowers of the Rocky Mountain region. Portland, Oregon: Timber Press. p. 181. ISBN 9781604696448.
  5. 1 2 3 4 Barnett, Don (2022). Penstemon of southeastern Colorado. Pueblo, CO.: Ethical Dessert. pp. 202–207. ISBN 978-0-578-37397-3.
  6. 1 2 3 4 5 Freeman, Craig C. "Penstemon virens - FNA". Flora of North America. Retrieved 26 January 2023.
  7. 1 2 3 4 5 Lindgren, Dale T. (2003). Growing penstemons : species, cultivars, and hybrids. Haverford, PA: Infinity Pub. pp. 91–92. ISBN 0741415291.
  8. 1 2 "Penstemon virens". Navigate.BotanicGardens.org. Denver Botanic Gardens. Retrieved 4 February 2023.
  9. ↑ University of Colorado Museum of Natural History Herbarium (2023). "botanydb.colorado.edu/index.php". University of Colorado Boulder. Retrieved 7 February 2023.
  10. ↑ Rydberg, Per Axel (1917). Flora of the Rocky Mountains and Adjacent Plains, Colorado, Utah, Wyoming, Idaho, Montana, Saskatchewan, Alberta, and neighboring parts of Nebraska, South Dakota, and British Columbia. New York, New York: The author. p. 773. Retrieved 27 January 2023.
  11. ↑ WFO (2023). "Penstemon virens Pennell ex Rydb". World Flora Online. Retrieved 27 January 2023.
  12. ↑ Lewis, Charlton T.; Short, Charles (1879). A Latin Dictionary. Oxford: Clarendon Press. Retrieved 27 January 2023.
  13. 1 2 "Penstemon virens". Wolfe Lab. Ohio State University. Retrieved 6 February 2023.
  14. ↑ NatureServe (2023). "Penstemon virens". NatureServe Explorer. Arlington, Virginia: NatureServe. Retrieved 12 June 2023.
  15. ↑ Beckrich, Kelsey (2018). Pollination Ecology in Penstemon: Mechanisms of Reproductive Isolation in Penstemon Virens and Penstemon Secundiflorus (Undergraduate Honors Thesis). University of Colorado. pp. 5–15. Retrieved 4 February 2023.
  16. ↑ Fornwalt, Paula J.; Kaufmann, Merrill R. (2014). "Understorey plant community dynamics following a large, mixed severity wildfire in a Pinus ponderosa–Pseudotsuga menziesii forest, Colorado, USA". Journal of Vegetation Science. 25 (3): 810, 815. ISSN 1100-9233. Retrieved 12 June 2023.
  17. ↑ Keith, Robin P.; Veblen, Thomas T.; Schoennagel, Tania L.; Sherriff, Rosemary L. (June 2010). "Understory vegetation indicates historic fire regimes in ponderosa pine-dominated ecosystems in the Colorado Front Range". Journal of Vegetation Science. 21 (3): 488–499. doi:10.1111/j.1654-1103.2009.01156.x. Retrieved 12 June 2023.
  18. ↑ Love, Stephen L; McCammon, Tony A (2017). "Compatible host/parasite pairs enhance propagation of paintbrush ( Castilleja spp.)". Native Plants Journal. 18 (3): 259, 260, 263. doi:10.3368/npj.18.3.252.
  19. ↑ "Penstemon virens (Front Range penstemon) - Recommended Plant List". www.fcgov.com. City of Fort Collins. Retrieved 6 February 2023.
  20. ↑ "Colorado Springs Utilities Xeriscaping - Blue Mist Penstemon". www.waterwiseplants.org. Colorado Springs Utilities. Retrieved 6 February 2023.
  21. 1 2 Henson, Y.; Langelo, L. (February 2021). "Growing Penstemons - 7.428". Colorado State Extension. Colorado State University. Retrieved 6 February 2023.
  22. ↑ "PlantFiles: Penstemon Species, Blue Mist Penstemon, Front Range Beard Tongue, Pride of the Mountain". Dave's Garden. Retrieved 6 February 2023.
  23. ↑ 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): 95. doi:10.3368/npj.21.1.83.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.