Eriophorum angustifolium, commonly known as common cottongrass or common cottonsedge, is a species of flowering plant in the sedge family, Cyperaceae. Native to North America, North Asia, and Northern Europe, it grows on peat or acidic soils, in open wetland, heath or moorland. It begins to flower in April or May and, after fertilisation in early summer, the small, unremarkable brown and green flowers develop distinctive white bristle-like seed-heads that resemble tufts of cotton; combined with its ecological suitability to bog, these characteristics give rise to the plant's alternative name, bog cotton.
Eriophorum angustifolium is a hardy, herbaceous, rhizomatous, perennial sedge, able to endure in a variety of environments in the temperate, subarctic and arctic regions of Earth. Unlike Gossypium, the genus from which cotton is derived, the bristles which grow on E. angustifolium are unsuited to textile manufacturing. Nevertheless, in Northern Europe, they were used as a substitute in the production of paper, pillows, candle-wicks, and wound-dressings. The indigenous peoples of North America use the plant in cooking and in the treatment of digestive problems. Following a vote in 2002, Plantlife International designated E. angustifolium the County Flower of Greater Manchester, as part of its British County Flowers campaign.
Description
In the wild, Eriophorum angustifolium is a creeping rhizomatous perennial sedge, with an abundance of unbranched, translucent pink roots. Fully grown, it has a tall, erect stem shaped like a narrow cylinder or triangular prism; it is smooth in texture and green in colour. Reports of the plant's height vary; estimates include up to , , and up to . E. angustifolium has "stiff grass-like foliage" consisting of long, narrow solidly dark green leaves, which have a single central groove, and narrow from their wide base to a triangular tip. Up to seven green and brown aerial peduncles and chaffs, roughly in size, protrude from umbels at the top of the stem from which achenes are produced after fertilisation, each with a single pappus; these combine to form a distinctive white perianth around long.
Eriophorum angustifolium is described as "a rather dull plant" in winter and spring, but "simply breathtaking" in summer and autumn, when 1–7 conspicuous inflorescences – composed of hundreds of white pappi comparable to cotton, hair, tassels, and/or bristles – stand out against naturally drab surroundings.
Eriophorum angustifolium differs from other species within the genus Eriophorum in its habitat and morphology. Its multiple flower heads and growth from rhizomes distinguish it from E. vaginatum, which has a single flower head and grows from dense tussocks. Although E. latifolium has 2–12 flower heads, it has laxly caespitose (tufted) growth, and its pappi are forked. The smooth peduncles and preference for acidic soil pH distinguishes E. angustifolium from E. gracile, which grows in swamp with a neutral pH and has scabrid (rough) peduncles.
Distribution and ecology
Distribution
Eriophorum angustifolium is native to the Northern Hemisphere, and distributed across Eurasia, North America and the British Isles, where there is open bog, heath, wetland and moorland, with standing water and calcareous peat or acidic soil. It can survive in the Subarctic and Arctic, and is found in Alaska, Finland and Greenland as far north as 83° N. The British botanist William Turner Thiselton-Dyer recorded E. angustifolium in the South African Republic in 1898.
In North America, Eriophorum angustifolium is found in the north from Alaska through Manitoba and the Canadian Prairies to Newfoundland and Labrador, down the Pacific Northwest and the state of Washington, across the Midwestern United States through Michigan and Iowa, down the Eastern Seaboard as far south-east as New York and New Jersey, and reaching as far south-west as New Mexico. In Eurasia, E. angustifolium is distributed throughout the Caucasus, European Russia and North Asia, including Siberia and the Kamchatka Peninsula, and south-east to Manchuria and Korea. It grows throughout continental Europe, with the exception of those parts within the Mediterranean Basin, growing in Scandinavia in the north, and as far south as the Norte Region of Portugal and the Pierian Mountains of Greece.