Juncaceae L.
Rush family.
Juncaceae, rush family.
Vegetative morphology. Plants perennial herbs; 3–50 cm high; caespitose, or not caespitose; with erect branched or unbranched stems arising close together, or with stems growing in more or less straight rows from a horizontal ground level stem. Ground-level or under-ground stems horizontal, or vertical and often branched, or not developed horizontally or vertically; rhizomatous, or stoloniferous; elongate, or compact. Aerial stems erect; circular or oval in cross-section; glabrous. Leaves in a basal tuft, or distributed along the stems (absent in Juncus arcticus); alternate; existing for a single season or less, or marcescent. Petioles absent. Ligules absent. Blades 10–250 mm long; 0.3–6 mm wide. Blades straight; linear; with blade auricles, or without auricles; circular in cross section, or flat, or involute, or folded, or convolute; veins parallel. Blades adaxial surface glabrous, or hairy. Blades adaxial surface hairs simple, unbranched. Blade margins with non-glandular hairs, or glabrous. Leaf apices acuminate (sometimes with calloused tips).
Reproductive morphology. Flowering stems present. Flowering stems with leaves, or without leaves; glabrous. Leaf or reduced bract closely associated with the base of the inflorescence present; conspicuous and leaf-like, or reduced, or scale-like. Flowers solitary (rare), or in inflorescences (usually). Inflorescence paniculate, or cymose, or head-like; terminal; dense, or diffuse; 0.4–8 cm long. Pedicels absent. Flowers per inflorescence 1–80; small, less than 5 mm in diameter or length, or medium-sized, 5–15 mm in diameter or length. Floral bracts apex entire, or lacerate. Calyx sepals 3; free. Calyx yellow, or brown; scarious; glabrous. Petals free; shorter than the calyx, or same length as the calyx; 3; yellow, or brown; ovate, or lanceolate; unlobed; 2.4–6.5 mm long. Stamens 6. Anthers 0.4–1.5 mm long. Gynoecia superior. Carpels syncarpous; 3. Styles 1. Stigmas per style 3. Ovules 3–100. Fruit sessile. Fruit with calyx persisting; dry; a capsule; ellipsoid, or ovoid, or elongate-cylindrical, or obovate; not distinctly flattened; dehiscent. Fruit 2.5–8 mm long; 1–3 mm wide; yellowish, or black, or brown. Styles may persist until dehiscence but are not modified. Seeds 3–100; 0.4–3.5 mm long; brown; with surfaces smooth.
Chromosome information. 2n = 12, 14, 20, 22, 24, 30, 36, 48, 60, 80, 120, 130–134.
Distribution. Northern hemisphere distribution: circumpolar, or amphi-Atlantic, or North American. Arctic, or low arctic. Range in the Canadian Arctic Archipelago widespread, or limited. Common, or uncommon, or rare.
Ecology and habitat. Substrates: wet meadows.
Notes. With two genera Juncus and Luzula.
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, L.J. Gillespie, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, A.K. Brysting and H. Solstad. 1999 onwards. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).