Eleocharis acicularis (L.) Roemer & J.A. Schultes
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 with branched or unbranched matted stems; less than 15 cm high; 2.5–10 cm high. Roots pallid-brown. Ground level or underground 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. Sheaths greyish brown, or brown. Ligules present. Blades straight; linear; circular in cross section (pressing flat); glabrous. Blades adaxial surface glabrous.
Flowering stems about as high as the leaves. Leaf or reduced bract closely associated with the base of the inflorescence absent (spike terminal). Inflorescence spicate; 0.3–0.6 cm long; 1–2 mm wide; 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 mid-vein 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. Styles base an enlarged bulge, separated from the top of the achene (which distinguishes this species from Trichophorum). Stigmas per style 3. Fruit 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. Substrate 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 localized 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 recognized as E. acicularis f. submersa (H. Nilss.) Norman, but this has not been widely taken up./par 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: Aiken, S.G., Boles, R.L., and Dallwitz, M.J. 1999 onwards. ‘Cyperaceae of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval.’ Version: 6th November 2000. http://http://www.mun.ca/biology/delta/arcticf/. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).
