Eriophorum vaginatum

Eriophorum vaginatum, the hare's-tail cottongrass,^[5] tussock cottongrass, or sheathed cottonsedge, is a species of perennial herbaceous flowering plant in the sedge family Cyperaceae. It is native to bogs and other acidic wetlands throughout the Holarctic kingdom. It is a 30–60 cm high tussock-forming plant with solitary spikes.

Eriophorum vaginatum is a 30– to 60-cm-high tussock-forming plant with extremely narrow, almost hair-like leaves. On the flowering stems there is a single, inflated leaf-sheath, without a lamina, hence the species epithet ("sheath" is "vagina" in latin). The inflorescence is a dense, tufted, solitary spike.^[6] Fruiting stems elongate considerably, reaching well above the leaves.

Eriophorum vaginatum, the type species of genus Eriophorum,^[7] was first described by the Swedish botanist Carl Linnaeus in 1753.^[3] Linnaeus based his diagnosis on specimens collected in the cold, barren regions of Europe ("habitat in Europae frigidis sterilibus").^[8]

In 1926, the American botanist Merritt Lyndon Fernald named and described Eriophorum spissum as a segregate taxon of Eriophorum vaginatum in northeastern North America.^[9][10] Fernald distinguished the two species based on spikelet shape, scale color, and anther size.^[11] In 1942, the Swedish botanist Oskar Eric Gunnar Hultén reduced Eriophorum spissum to a subspecies,^[12] and in 1967, the Canadian botanist Joseph Robert Bernard Boivin further reduced it to a variety.^[13] As of March 2026, the name Eriophorum vaginatum subsp. spissum (Fernald) Hultén is accepted by some authorities,^[14][15][16] while others accept the name Eriophorum vaginatum var. spissum (Fernald) B.Boivin.^[17][18][19] Still others accept a broadly defined Eriophorum vaginatum L.^[1][4][20]

Fernald simultaneously published the names Eriophorum spissum and Eriophorum spissum var. erubescens in 1926.^[9][21][22] The latter was first described as Eriophorum callitrix var. erubescens by Fernald in 1905 based on a specimen collected in Newfoundland.^[23][24] Boivin reduced the variety to a form of Eriophorum vaginatum in 1992.^[25][26] As of March 2026, some authorities consider the three infraspecific names with epithet erubescens to be synonyms of Eriophorum vaginatum L.^[4][20] Others consider them to be synonyms of the hybrid Eriophorum × pylaieanum Raymond.^[27][28]

Eriophorum vaginatum occurs throughout the subarctic and temperate regions of the Northern Hemisphere. In Eurasia, its range extends from Spain in southwestern Europe to Japan in East Asia, northward to Siberia and Scandinavia.^[4] In North America, it occurs from Alaska south to British Columbia, east through the Great Lakes region to New England, and north to Greenland.^[6] It prefers acidic, moist to wet, peaty soil and may be dominant in bogs, poor fens, and the heathlands of Western Europe. In the Arctic, it is commonly found in the peaty tundras of Russia and North America.^[29] It is common in Scotland where it is sometimes referred to as draw-ling or drawmoss.^[30][31]

In Merionethshire, Wales, seasonal growth of Eriophorum vaginatum begins around mid-March and continues until the end of November. In the southern Pennines in Northern England, it is in full fruit by June. Peak flowering occurs in May but flowering can occur in April or even as early as March. In the northern Pennines, there is a second flowering period during September and October.^[32]

• Boivin, Bernard (1992). Les Cypéracées de l’est du Canada (PDF). Provancheria No. 25. Québec: Université Laval. Retrieved 20 March 2026.
• Fernald, M. L. (May 1905). "The North American species of Eriophorum. Part 1: Synopsis of American species". Rhodora. 7 (77): 81–92. Retrieved 17 March 2026.
• Fernald, M. L. (1925). "The identity of Eriophorum callitrix". Rhodora. 27 (324): 203–210. Retrieved 15 March 2026.
• 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. ISBN 978-0-300-17154-9.
• Linnaeus, Carl (1753). Species Plantarum: exhibentes plantas rite cognitas, ad genera relatas, cum differentiis specificis, nominibus trivialibus, synonymis selectis, locis natalibus, secundum systema sexuale digestas (1st ed.). Stockholm: Impensis Laurentii Salvii. Retrieved 3 August 2023.
• Parker, Thomas C.; Unger, Steven L.; Moody, Michael L.; Tang, Jianwu; Fetcher, Ned (2022). "Intraspecific variation in phenology offers resilience to climate change for Eriophorum vaginatum". Arctic Science. 8 (3): 935–951. doi:10.1139/as-2020-0039.
• Scoggan, H. J. (1978). The Flora of Canada. National Museum of Natural Sciences (Canada). Retrieved 19 March 2026.
• Tucker, G. C. (1987). "The genera of Cyperaceae in the southeastern United States". Journal of the Arnold Arboretum. 68 (4): 361–445. JSTOR 43782578.
• Wein, Ross W. (July 1973). "Eriophorum vaginatum L.". Journal of Ecology. 61 (2): 601–615. doi:10.2307/2259047. JSTOR 2259047.

• "Eriophorum vaginatum (Tussock Cottongrass)". Minnesota Wildflowers. Retrieved 29 November 2024.
• Reznicek, A. A.; Voss, E. G.; Walters, B. S. (February 2011). "Eriophorum vaginatum L.". Michigan Flora Online. University of Michigan. Retrieved 15 March 2026.
• "Eriophorum vaginatum L.". Global Biodiversity Information Facility. Retrieved 15 March 2026.
• Kartesz, John T. (2014). "Eriophorum vaginatum". State-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). Retrieved 15 March 2026.
• Kartesz, John T. (2014). "Eriophorum vaginatum". County-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). Retrieved 15 March 2026.
• Aiken, S.G.; Dallwitz, M.J.; Consaul, L.L.; McJannet, C.L.; Boles, R.L.; Argus, G.W.; Gillett, J.M.; Scott, P.J.; Elven, R.; LeBlanc, M.C.; Gillespie, L.J.; Brysting, A.K.; Solstad, H.; Harris, J.G. (2007). "Eriophorum vaginatum L.". Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada. Retrieved 25 September 2025.