Eriophorum virginicum var. confertissimum (Alph.Wood) Alph.Wood
Eriophorum virginicum var. gracile Torr.
Eriophorum virginicum, the tawny cottongrass, is a species of flowering plant in the sedge familyCyperaceae. It is native to eastern North America but was introduced into both British Columbia and Washington in western North America. It is most common in eastern Canada, New England, and the Great Lakes region. It is the only species of Eriophorum in North America that occurs in the southeastern United States, where it is uncommon. The common name refers to the tawny color of its fruiting head. Despite the name, it is a sedge, not a grass, and it is sometimes called tawny cottonsedge to emphasize this fact.
Description
Eriophorum virginicum is a perennialherbaceous plant that forms colonies by means of long-creeping rhizomes. Each stem (or culm) in the colony grows to 120 cm (47 in) long. The terminal inflorescence comprises 2–10 spikelets, each on a peduncle between 2 and 10 mm long. The inflorescence is subtended by 2–5 leaf-like bracts, the longest of which is 4 to 12 cm (2 to 5 in) in length. Individual flowers have 10 or more perianth bristles that are brown in color (at least at the base). Rarely the bristles are entirely white.[4][5]
Typically the fruiting head is densely packed, which tends to obscure the spikelets. Despite this, Eriophorum virginicum is rather easy to distinguish from other cottongrasses due to its late fruiting time and distinctive color.[6]
Eriophorum virginicum was segregated to a new genus Eriophoropsis by the Austrian botanist and mycologist Eduard Palla in 1896.[8] Later, in 1958, it was segregated to the existing genus ScirpusTourn. ex L. by the Japanese botanist and collector Tetsuo Michael Koyama.[9] As of July 2024[update], both Eriophoropsis virginica(L.) Palla and Scirpus virginicus(L.) T.Koyama are considered to be synonyms for Eriophorum virginicumL.[10][11]
Eriophorum virginicum var. album was described by the American botanist Asa Gray in 1876.[12] Variety album has white (not brown) bristles. In 1924, the American botanist Karl McKay Wiegand reduced the variety to forma.[13] Both names are considered to be synonyms for Eriophorum virginicumL.
Eriophorum virginicum, together with Eriophorum tenellum and Eriophorum gracile, form a strongly supported clade that is sister to the rest of the genus. The clade is distinguished by having glumes (scales at the base of each flower in a spikelet) with many prominent nerves whereas the glumes of the remaining species possess a single prominent midnerve.[14]
Distribution and habitat
Eriophorum virginicum is native to eastern North America, from Newfoundland and Labrador in Canada to South Carolina in the United States (U.S.), ranging as far west as Minnesota.[3] It was introduced into British Columbia in western Canada,[15] where it is confined to bog habitat in the Fraser Valley.[16] It was also introduced into similar habitat in Skagit County, Washington.[17] In the U.S., it is most common in New England and the Great Lakes region.[18] It is the only species of Eriophorum in North America that occurs in the southeastern U.S.,[19] where it is least common. Disjunct populations occur throughout the southeastern states, with the southernmost population occurring in Taylor County, Georgia.
Eriophorum virginicum is a perennialflowering plant that flowers in the early summer. After the flowers are pollinated, cotton-like fruiting heads develop between mid-summer and early autumn.[4] In Minnesota, for example, fruiting occurs from July to September.[24]
^"Eriophorum virginicum". State-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). 2014. Retrieved 6 July 2024.
^"Eriophorum virginicumL.". E-Flora BC: Electronic Atlas of the Plants of British Columbia. Retrieved 27 November 2024.
^"Eriophorum virginicum". Burke Museum Herbarium, University of Washington. Retrieved 27 November 2024.
^"Eriophorum virginicum". County-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). 2014. Retrieved 6 July 2024.
^"Eriophorum". State-level distribution maps from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). 2014. Retrieved 6 July 2024.
Gilman, Arthur V. (2015). New Flora of Vermont. Memoirs of The New York Botanical Garden, Volume 110. Bronx, New York, USA: The New York Botanical Garden Press. ISBN978-0-89327-516-7.
Haines, Arthur (2011). New England Wild Flower Society's Flora Novae Angliae: A Manual for the Identification of Native and Naturalized Higher Vascular Plants of New England. Illustrated by Elizabeth Farnsworth and Gordon Morrison. Yale University Press. ISBN978-0-300-17154-9.
"Eriophorum virginicum". Lady Bird Johnson Wildflower Center. The University of Texas at Austin. Retrieved 6 July 2024.
Weakley, Alan S.; Southeastern Flora Team (2024). "Eriophorum virginicumLinnaeus". Flora of the southeastern United States. University of North Carolina Herbarium, North Carolina Botanical Garden. Retrieved 10 July 2024.
"Eriophorum virginicum". North Carolina Extension Gardener Plant Toolbox. Retrieved 10 July 2024.