Eleocharis acicularis (L.) Roemer & J.A. Schultes
Cyperaceae, sedge family.
Syst. II, 154. 1817.
Eleocharis acicularis var. occidentalis Svens.
Eleocharis acicularis var. typica Svens.
Eleocharis reverchonii Svens.
Eleocharis acicularis f. submersa (H. Nilss) Norman
Scirpus acicularis L.
Plants caespitose; tiny aquatic with bristle-like leaves from a filiform stem buried in the mud; less than 15 cm high; 2.5–10 cm high. Roots pallid-brown. Ground-level or under-ground stems horizontal; rhizomatous, or stoloniferous (depending on the substrate); compact. Scales present (on horizontal stems). Aerial stems erect; filiform (0.1–0.2 mm in diameter); circular or oval in cross-section; glabrous. Leaves mostly basal. Petioles absent. Sheaths breaking down into fibres; not forming a conspicuous build up at the base of the plant; greyish brown, or brown; collars collars absent. Ligules present. Blades 10–60 mm long; 0.4–0.6 mm wide; straight; linear; circular in cross section (pressing flat); with parallel veins; adaxial surface glabrous. Blades abaxial surface glabrous. Leaf margins glabrous.
Flowering stems about as high as the leaves; without leaves. Leaf or reduced bract closely associated with the base of the inflorescence absent (spike terminal). Inflorescences spicate; inflorescence 0.3–0.6 cm long; inflorescence 1–2 mm wide; inflorescence a single spike. Terminal spike with both sexes in each floret (no fertile specimens are known from the Arctic Archipelago). Flowers small, less than 5 mm in diameter or length. Floral scales green (reddish); with margins, and sometimes midvein paler in colour than the adjacent area of the scale; ovate, or lanceolate; 2–3 mm long; 1.2–1.8 mm wide; glabrous. Perianth represented by bristles; bristles inconspicuous. Anthers 1–1.4 mm long. Carpels syncarpous. Styles base an enlarged bulge, separated from the top of the achene (which distinguishes this species from Trichophorum). Stigmas per style 3. Placentation basal. Fruit surrounded by perianth persisting as bristles; an achene; 0.9–1.1 mm long; straw coloured.
Chromosome information. 2n = 20.
Distribution. Circumpolar. Low arctic. Range in the Canadian Arctic Archipelago limited. Rare. Arctic Islands: Baffin (Iqaluit, Great Plain of the Koukdjuak (both new since Porsild, 1957) and Kimmirut).
Ecology and habitat. Substrates, wet meadows, around the margins of ponds; aquatic; halophytic; silt; with high organic content. Forms soft green carpets on the bottom of ponds near Carex chordorrhiza. In the Great Plain of the Koukdjuak, it was found localised in an expansive saline plain, growing thinly in bare clay with occasional Chrysosplenium tetrandrum.
Notes. Polunin (1940) noted that this plant was first found in the Canadian Arctic Archipelago at Kimmirut in 1936, submersed in bed of small freshwater ponds in marshy lowland areas a few miles inland. It has since been found in Iqaluit. In the Arctic Archipelago as is usually the case in Greenland the plants are submersed and entirely sterile. He suggested that this might be recognised as E. acicularis f. submersa (H. Nilss.) Norman, but this has not been widely taken up.
Porsild (1957), gave the authority for the generic name as Lineaus, but this was a mistake as the genus was described by Robert Brown.
Illustrations. • Arctic Island distribution.
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L.Consaul, R.L. Boles, R. Elven and M.E. LeBlanc. 2001 onwards. Flora of the Canadian Arctic Archipelago. Volume 1. Pteridophytes and Monocotyledons: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 16th March 2001. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993, 1995, 2000), and Aiken, Dallwitz et al. (1999) should also be cited (see References).
