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 30âÂÂ60 cm high tussock-forming plant with solitary spikes.
Eriophorum vaginatum is a perennial, -forming . It has a growth habit, with multiple flowering stems at the base of the plant. A stem may reach up to tall, with a persistent brown 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 ). The uppermost sheath is conspicuously inflated. The inflorescence is a single erect at the tip of the stem. The spikelet bears numerous , each covered by a scale . At the base of the inflorescence, there are 10 or more empty scales , the lowermost scales becoming spreading or reflexed at maturity. The flower parts emerge from the 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, the type species of genus Eriophorum, was first described by the Swedish botanist Carl Linnaeus in 1753. Linnaeus based his 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. , the name Eriophorum vaginatum subsp. spissum is accepted by some authorities, while others accept the name Eriophorum vaginatum var. spissum . Still others accept a broadly defined Eriophorum vaginatum
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 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. , the accepted name of this taxon is Eriophorum ÃÂ pylaieanum .
The specific epithet vaginatum, which means "having a sheath", refers to an important character used to recognize this species. Both the scientific name and the common name "sheathed cottongrass" emphasize this fact. The epithet spissum, which means dense or crowded, evidently refers to the densely cespitose growth habit of this species. In Britain and Ireland, it 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.
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.
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.