Hare's-tail cottongras

Eriophorum vaginatum, also known as hare's-tail cottongrass, 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.

Description

Eriophorum vaginatum is a perennial, tussock-forming sedge. It has a cespitose (tufted) growth habit, with multiple flowering stems at the base of the plant. A stem may reach up to 60 cm (24 in) tall, with a persistent brown sheath at its base. Basal leaves are approximately 1 mm wide and noticeably shorter than the flowering stem. There are 1–3 leaves along the length of the stem, each reduced to a sheath (no leaf blade). The uppermost sheath is conspicuously inflated. The inflorescence is a single erect spikelet at the tip of the stem. The spikelet bears numerous florets, each covered by a scale (a type of bract in sedges and grasses). At the base of the inflorescence, there are 10 or more empty scales (with no flowers), the lowermost scales becoming spreading or reflexed at maturity. The flower parts emerge from the axils of the floral scales. After pollination, each floret develops 10 or more white bristles that elongate to 2 cm at maturity. The fruit is a small brown nutlet no more than 3.5 mm long.

For identification purposes, the cottongrasses divide into two groups based on the number of spikelets. Eriophorum vaginatum is a member of the unispicate group since it has one (not multiple) spikelets. It is similar in appearance to the unispicate species Eriophorum brachyantherum and Eriophorum callitrix. All three species have densely tufted stems (cespitose) and 10 or more empty scales at the base of the inflorescence. Eriophorum vaginatum is distinguished by having white-margined empty scales with the lowermost scales spreading or reflexed (not appressed to ascending), a conspicuously inflated sheath, and a tussock-forming growth habit.

Eriophorum vaginatum subsp. spissum is very similar to the typical subspecies described above, differing in a few characters only:

Subspecies spissum is a smaller plant with a more compact tussock. It occurs throughout northeastern North America but the full extent of its range is unknown.

Taxonomy

Eriophorum vaginatum, the type species of genus Eriophorum, was first described by the Swedish botanist Carl Linnaeus in 1753. Linnaeus based his diagnosis on specimens with smooth sheathed culms collected in the cold, barren regions of Europe.

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

Fernald simultaneously published the names Eriophorum spissum and Eriophorum spissum var. erubescens in 1926. The latter was first described as Eriophorum callitrix var. erubescens by Fernald in 1905 based on a specimen collected in Newfoundland. The epithet erubescens, which means "turning red", refers to the color of the perianth bristles. In 1951, the Canadian botanist Louis-Florent-Marcel Raymond described a hybrid of Eriophorum russeolum and Eriophorum vaginatum subsp. spissum, placing Eriophorum spissum var. erubescens (Fernald) Fernald in synonymy with the hybrid name. In 1992, Boivin reduced Eriophorum spissum var. erubescens to a form of Eriophorum vaginatum var. spissum. He listed Raymond's hybrid name as a synonym of the new form. As of March 2026, the accepted name of this taxon is Eriophorum × pylaieanum Raymond.

Etymology

The specific epithet vaginatum, which means "having a sheath", refers to an important character used to recognize this species. Both the scientific name Eriophorum vaginatum and the common name "sheathed cottongrass" emphasize this fact. The epithet spissum, which means dense or crowded, evidently refers to the compact tussock of this subspecies. In Canada, the subspecies is known as "dense cottongrass". In Britain and Ireland (and elsewhere), the species is referred to as "hare's-tail cottongrass", a name also used by Fernald in 1950. The name "tussock cottongrass" gained in popularity after its publication in Flora of North America in 2002.

Distribution and habitat

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. In North America, it occurs from Alaska south to British Columbia, east through the Great Lakes region to New England, and north to Greenland. 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. It is common in Scotland where it is sometimes referred to as draw-ling or drawmoss.

Ecology

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.

References

Bibliography

• 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.
• Fernald, Merrit Lyndon (1970) [First published 1950]. Rollins, R. C. (ed.). Gray's Manual of Botany (8th ed.). D. Van Nostrand Company. ISBN 0-442-22250-5.
• Gledhill, David (2008). The Names of Plants (4th ed.). Cambridge University Press. ISBN 978-0-521-86645-3. Retrieved 21 February 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.

External links

• 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.