Trichophorum caespitosum (L.) Hartman
Baeothryon caespitosum (L.) Dietr.,
Scirpus caespitosus L.
Trichophorum austriacum Pall.
Scirpus caespitosus L. subsp. austriacus (Pallas) Asch. & Graebn.
Scirpus caespitosus var. callosus Bigel.
Plants caespitose. Plants less than 15 cm high; 7–15 cm high. Roots pallid-brown. Ground level or underground stems not developed horizontally or vertically. Scales present. Aerial stems erect; filiform (wiry, 0.4–0.6 mm in diameter); circular or oval in cross section; glabrous. Leaves mostly basal. Sheaths greyish brown. Ligules present. Blades straight; linear; flat (or slightly folded, bract-like, callous tipped, and easily overlooked); glabrous. Blades adaxial surface glabrous.
Flowering stems conspicuously taller than the leaves. Leaf or reduced bract closely associated with the base of the inflorescence present; reduced, or scale-like; similar in length to the inflorescence; 0.3–0.6 cm long; with sheath shorter than the blade. Inflorescence spicate; 0.3–0.6 cm long; 1.5–3 mm wide; a single spike. Individual spike(s) erect. Terminal spike with both sexes in each floret. Floral scales orange brown (often with empty scales between the reduced leaf and the florets); with margins paler than body of scale; ovate; 2–4 mm long; 1.8–2.2 mm wide; glabrous. Perianth represented by bristles; bristles inconspicuous. Anthers 2–2.5 mm long. Styles base not enlarged, continuous with the achene (which distinguishes this species from Eleocharis). Styles 1. Stigmas per style 3. Fruit not surrounded by a perigynium.
Chromosome information. 2n = 104.
Distribution. Circumpolar. Low arctic. Range in the Canadian Arctic Archipelago limited. Rare. Arctic Islands: Baffin (Beekman Peninsula (new since Porsild, 1957), Cormack Bay and Kimmirut).
Ecology and habitat. Substrate hummocks (peaty), along streams, tundra (in damp hollows), slopes (in springy or grassy places); imperfectly drained, or on seepage slopes; calcareous; with high organic content, or peat.
Notes. Polunin (1940) noted that all material in the Canadian Eastern Arctic has the orifice of the upper sheath "short" and with a firm border, and the spikelets short and few-flowered, and thus belongs not to the European lowland head form but to the wide ranging "arctic-alpine" var. callosus Bigel. but this has not been widely taken up.
Illustrations. • Herbarium specimen. Tufted plants with wiry stems topped with small unispicate inflorescences. CAN 29185. • Close-up of inflorescence. Three solitary spikes at anthesis, each subtended by a bract. CAN 29185. • 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).
