Cyperaceae of the Canadian Arctic Archipelago

S.G. Aiken, R.L. Boles, and M.J. Dallwitz

Carex capitata Sol.

Syst. Nat. ed. 10, II, p. 1261. 1759.

Nomenclatural section used by Flora of North America project subgenus Carex, sect. Capitatae Mackenzie

Carex capitata L. subsp. capitata

Carex capitata subsp. arctogena H. Sm.

Carex arctogena H. Sm.

Carex capitata var. arctogena (H. Sm.) Hultén

Plants caespitose. Plants less than 15 cm high (Arctic Islands), or more than 15 cm high (Continental Northwest Territories); 4–10(–25) cm high. Roots pallid-brown, or black. Ground level or underground stems not developed horizontally or vertically. Scales present. Aerial stems erect; filiform (0.4–0.6 mm in diameter); triangular in cross section; glabrous. Leaves mostly basal. Sheaths forming a conspicuous build up at the base of the plant; greyish brown, or green. Ligules present. Blades straight; linear; triangular in cross section, or folded; hairy (scaberulous on midvein and margins).

Flowering stems about as high as the leaves, or conspicuously taller than the leaves. Leaf or reduced bract closely associated with the base of the inflorescence absent. Inflorescence spicate, or head-like; globose or subglobose; 0.5–0.8(–1) cm long; 4–6 mm wide; a single spike. Individual spike(s) erect. Terminal spike staminate at the apex. Cladoprophyll present at the base of the peduncle of lateral spikes. Staminate flowers conspicuous (forming a small projecting tuft at the top of the spike). Floral scales shorter than the perigynium in fruit; orange brown; with margins, and sometimes mid-vein paler in colour than the adjacent area of the scale (margins a wide translucent zone); ovate; 1.5–2.5 mm long; 1.5–2 mm wide; glabrous. Perianth absent. Anthers 1–1.5 mm long. Styles slender, extending beyond the beak. Stigmas per style 2. Fruit surrounded by a perigynium. Perigynia fused to the apex except for a small aperture through which the style protrudes; broadly ovate; 1.9–2.5(–3.5) mm long; 1.5–2 mm wide; sessile; erect or ascending; straw-coloured, or green (pale); surface dull; glabrous; appearing nerveless; inflated; apices beaked with a long beak; apex oblique, becoming slightly bidentate. Achenes not filling the upper part of the perigynia; lenticular.

Chromosome information. 2n = 50.

Distribution. Amphi-Atlantic. Low arctic. Range in the Canadian Arctic Archipelago limited. Rare. Arctic Islands: Baffin (Porsild and Cody(1980) mapped two records from southern Baffin Island that we have not traced.).

Ecology and habitat. Substrate river terraces, tundra; imperfectly drained; with high organic content.

Notes. Treated as Carex arctogena H.Sm., Porsild (1957). P. Ball (personal communication, 1997) indicated that subsp. arctogena is not a recognizable entity. Carex capitata is very rare in the Arctic Islands. Polunin (1940) recorded collecting the species 8 miles inland from Kimmirut with Pinguicula vulgaris and suggested that as both taxa were new to the entire Arctic Archipelago "it certainly looks as if they may have been brought in together by some bird or beast".

Illustrations. • Close-up of inflorescence. Unispicate inflorescence with a tuft of staminate flowers at the apex and pistillate flowers at the base, perigynia with long beaks. • Arctic Island distribution.