Trichophorum caespitosum (L.) Hartman
Cyperaceae, sedge family.
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 (densely); with wiry, smooth, erect ascending culms; less than 15 cm high; 7–15 cm high. Roots pallid-brown. Ground-level or under-ground stems not developed horizontally or vertically underground. Scales present. Aerial stems erect; filiform (wiry, 0.4–0.6 mm in diameter); circular or oval in cross-section; glabrous. Leaves mostly basal. Petioles absent. Sheaths persisting; forming a conspicuous build up at the base of the plant (composed of sheaths and flat scales 2–3 mm wide); greyish brown; collars collars absent. Ligules present. Blades 5–30 mm long; 0.2–1 mm wide; straight; linear; flat (or slightly folded, bract-like, callous tipped, and easily overlooked); with parallel veins; adaxial surface glabrous. Blades abaxial surface glabrous. Leaf margins glabrous. Plants bisexual.
Flowering stems conspicuously taller than the leaves; with leaves. Leaf or reduced bract closely associated with the base of the inflorescence present; reduced, or scale-like; similar in length to the inflorescence; 3–6 mm long; with sheath shorter than the blade; persistent. Inflorescences spicate; inflorescence 0.3–0.6 cm long; inflorescence 1.5–3 mm wide; inflorescence 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. Carpels syncarpous. Styles base not enlarged, continuous with the achene (which distinguishes this species from Eleocharis). Styles 1. Stigmas per style 3. Placentation basal. Fruit surrounded by perianth persisting as bristles (that are inconspicuous); an achene.
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. Substrates, hummocks (peaty), along streams, tundra (in damp hollows), slopes (in springy or grassy places); imperfectly drained moist areas, on seepage slopes; calcareous; with high organic content, or peat. In mucky, peaty sites; often on seepage slopes.
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. 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: ‘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).
