Eriophorum

Eriophorum (cottongrass, cotton-grass or cottonsedge) is a genus of flowering plants in the family Cyperaceae, the sedge family. They are found in the cool temperate, alpine, and Arctic regions of the Northern Hemisphere, primarily in the middle latitudes of North America, Europe, and Asia.

Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Clade: Commelinids
Order: Poales
Family: Cyperaceae
Genus: Eriophorum

Description

Eriophorium species are perennial herbaceous plants that persist by means of underground rhizomes. Stems (called culms) grow singly or in clumps (i.e., cespitose). Both basal leaves and stem leaves are present, although the latter are bladeless in some species. The terminal inflorescence is either a single erect spikelet or multiple spikelets on peduncles of various lengths. In the case of multiple spikelets, the inflorescence is subtended by one or more leaf-like bracts. Individual flowers have 10 or more smooth perianth bristles that greatly elongate and remain attached to the achene during fruiting. The bristles facilitate seed dispersal by wind. In cold Arctic regions, the bristles also serve as insulation by trapping solar radiation and thereby increasing the temperature of the reproductive organs.

Identification keys often begin with a pair of alternatives that implicitly divide the genus into two mutually exclusive sections:

• Eriophorum section Vaginata: one spikelet, without involucral bracts
• Eriophorum section Phyllanthela: multiple spikelets (rarely one), subtended by one or more leaf-like bracts

Besides the number of spikelets and the presence of bracts, other characters may be used for identification, including: the length of the uppermost leaf blade relative to its sheath; the number of bracts (0, 1, or more than 1); the length and orientation of the bracts; the length of the peduncles; and the color of the bristles.

Taxonomy

In the first edition of Species Plantarum published in 1753, the Swedish botanist Carl Linnaeus established genus Eriophorum by recognizing four species: Eriophorum vaginatum, Eriophorum polystachion, Eriophorum virginicum, and Eriophorum alpinum. In the second edition published in 1762, Linnaeus added a fifth species, Eriophorum cyperinum. The name Eriophorum L. is the primary generic name in use today. Although the names of some of the species have changed, the number of recognized taxa in genus Eriophorum has remained more-or-less the same since 1994.

In the fifth edition of Genera Plantarum published in 1754 (intended to accompany the first edition of Species Plantarum), Linnaeus referenced the prior work of the Italian botanist Pier Antonio Micheli and the French botanist Joseph Pitton de Tournefort.[14] In 1729, Micheli described genus Linagrostis, including an illustration of an unidentified plant. (The plant was later identified to be Eriophorum vaginatum.) Tournefort coined the French name Linaigrette (Latin: Linagrostis) in 1694, but his contribution became better known in Europe when his book was translated to Latin in 1719.

The French naturalist and mineralogist Jean-Étienne Guettard resurrected the pre-Linnaean name Linagrostis in 1750, and again in 1754, but Linagrostis Guett. is regarded as a synonym for Eriophorum L. After Guettard, the name Linagrostis was redescribed by numerous botanists, including John Hill (1756), Johann Gottfried Zinn (1757), and Giovanni Antonio Scopoli (1771), but all three published illegitimate names since Linagrostis Guett. takes precedence. Scopoli's description of Linagrostis Tourn. ex Scop. is notable, however, since it is explicitly based on the early work of Tournefort. The names Linagrostis vaginata (L.) Scop., Linagrostis alpina (L.) Scop., and Linagrostis polystachia (L.) Scop. are synonyms for the corresponding names introduced by Linnaeus in 1753.

The Austrian botanist and mycologist Eduard Palla established genus Eriophoropsis in 1896 by segregating Eriophorum virginicum into a new genus. The name Eriophoropsis Palla is both a synonym for Eriophorum L. and the basionym of Eriophorum subgen. Eriophoropsis (Palla) Raymond, the latter described by the Canadian botanist Louis-Florent-Marcel Raymond in 1954.
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