Common Cotton-Grass

Appearance

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 60 cm, 15–75 cm, and up to 100 cm. "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 2–6-millimetre wide base to a triangular tip. Up to seven green and brown aerial peduncles and chaffs, roughly 4–10 millimetres 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 5 centimetres 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 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 peduncles.

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.

"Eriophorum angustifolium" is the most common of the four native species of "Eriophorum" in the British Isles, and has been recorded as having existed in all vice-counties, thriving particularly well in Ireland and northern and western regions of Great Britain, but less so in southern and eastern areas. In the mires of Northern Ireland and the South Pennines, it considered a ruderal, pioneer and keystone species, because it can quickly colonise and repair damaged or eroded peat, encourage the re-vegetation of its surroundings, and retain sediment and its landscape to serve as a carbon sink. In central and southern counties of England, the species is rare or absent, and was "completely destroyed" in Cambridgeshire, The Broads, The Fens and other parts of the East of England by human activities such as land reclamation. Within the British Isles, "E. angustifolium" thrives at a range of altitudes from sea-level fens and lowland meadows, to exposed upland moors when provided with a habitat of acid bog or waterlogged heath. It has an altitudinal limit of 1,100 metres above sea level, reaching 854 metres in the Wicklow Mountains of Ireland, and 1,060 metres in the Scottish Highlands.

Status

"Eriophorum angustifolium" has a NatureServe conservation status of G5, meaning that the species is considered to be ecologically secure by NatureServe, lacking any threats to its global abundance.

Habitat

"Eriophorum angustifolium" is a hardy, herbaceous, rhizomatous, perennial plant, meaning that it is resilient to cold and freezing climatic conditions, dies back at the end of its growing season, has creeping rootstalks, and lives for over two years. It grows vigorously from seed over a period of 2–5 years, and thrives particularly well in freshly disturbed, cut or eroded peat. "E. angustifolium" is protogynous.

Sexual reproduction in "Eriophorum angustifolium" begins with flowering in spring or early summer, when groups of 3–5 brown flowers are produced. Fertilisation usually takes place in May or June, via anemophily, and the white bristle-like perianth, composed of achenes with pappi then grows outwards to appear like short tufts of cotton thread. These pappi endure well into summer, lasting from around June to September. Like the pappus of "Taraxacum", this aids in wind-dispersal, and also serves as thermal insulation, conserving the temperature of the plant's reproductive organs by trapping solar radiation.

It is a known host to the fungal species "Myriosclerotinia ciborium", "Hysteronaevia advena", "Lachnum imbecille" and "Lophodermium caricinum".

Cultural

"Eriophorum angustifolium" seeds and stems are edible and are used in traditional Native American cuisine by Alaska Natives, Inuit and Inupiat people. The leaves and roots of "E. angustifolium" are also edible and, because of their astringent properties, used by the Yupik peoples for medicinal purposes, through a process of decoction, infusion or poultice, to treat ailments of the human gastrointestinal tract, and in the Old World for the treatment of diarrhoea. In abundance, "E. angustifolium" can grow with enough density to disguise wetland and bog. Consequently, it may be used as a natural indicator of areas which are hazardous and to avoid travelling through. Attempts to make a cotton-like thread from the hairs of the plant's seed-heads have been thwarted by its brittleness, but it has been used in the production of paper and candle wicks in Germany, and was used as a feather substitute in pillow stuffing in Sweden and Sussex, England. In Scotland, during World War I, it was used to dress wounds.

In 2002, the County Flowers campaign of Plantlife International, which asked members of the public to nominate and vote for a wildflower emblem for each of the counties and metropolitan areas of the United Kingdom, resulted in "Eriophorum angustifolium" being announced as the County Flower of Greater Manchester.