Juncaceae L.
Rush family.
Juncaceae, rush family.
Plants herbs; perennial herbs; 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; less than 15 cm high, or more than 15 cm high; 3–50 cm high; not vegetatively proliferating by bulbils; without milky juice; not glandular viscid. Taproot absent. Ground-level or under-ground stems horizontal, or vertical and often branched, or not developed horizontally or vertically underground; rhizomatous, or stoloniferous; elongate, or compact. Aerial stems erect; not conspicuously jointed; not filiform; circular or oval in cross-section; glabrous. Branches not glaucous; epidermis not flaky. Leaves mostly basal, or distributed along the stems (absent in Juncus arcticus); alternate; not distinctly distichous; simple; not heterophyllous; deciduous, or marcescent. Stipules absent. Petioles absent. Ligules absent. Blades 10–250 mm long; 0.3–6 mm wide; herbaceous; straight; linear; with blade auricles, or without auricles; circular in cross section, or flat, or involute, or folded, or convolute; with parallel veins; not septate nodulose; glabrous, or hairy; adaxial surface dull. Hairs on blades simple, unbranched without glands. Leaves not lobed. Leaf margins entire; with non-glandular hairs, or glabrous. Conspicuous hydathodes absent. Leaf apices acuminate (sometimes with calloused tips). Plants bisexual.
Flowering stems with leaves, or without leaves; glabrous. Flowering culm nodes not rooting at the lower nodes. Flag leaf sheaths not inflated. Leaf or reduced bract closely associated with the base of the inflorescence present; conspicuous and leaf-like, or reduced, or scale-like; persistent; without calloused tip. Flowers solitary (rare), or in inflorescences (usually). Inflorescences paniculate, or cymose, or head-like; inflorescence terminal; inflorescence dense, or diffuse; inflorescence 0.4–8 cm long; inflorescence without bulbils. Bisexual spike(s) without empty bracts at the base. Involucral bracts 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; sessile or subsessile; bisexual; actinomorphic. Floral scales not reflexed; not falling early. Floral bracts apex entire, or lacerate. Callus not differentiated. Perianth present. Calyx present; sepals 3; sepals free; yellow, or brown; scarious; non-accrescent; glabrous. Petals present; 3; free; yellow, or brown; without contrasting markings; ovate, or lanceolate; unlobed; not tipped with an awn-like bristle; 2.4–6.5 mm long; not spurred; shorter than the calyx, or same length as the calyx. Stamens 6; filaments all equal in length; free of the corolla. Anthers 0.4–1.5 mm long. Nectaries absent. Carpels syncarpous; 3. Gynoecia superior. Styles present. Styles completely fused; base not enlarged, continuous with the achene. Styles 1. Stigmas per style 3. Placentation axile. Ovules 3–100. Fruit with calyx persisting; a capsule; ellipsoid, or ovoid, or elongate-cylindrical, or obovate; not distinctly flattened; dehiscent; 2.5–8 mm long; 1–3 mm wide; sessile; dry; yellowish, or black, or brown; glabrous. Legume valves straight. Styles may persist until dehiscence but are not modified. Seeds 3–100; 0.4–3.5 mm long; brown; smooth.
Chromosome information. 2n = 12, 14, 20, 22, 24, 30, 36, 48, 60, 80, 120, 130–134.
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. Canada.
Ecology and habitat. Substrates, wet meadows.
Notes. With two genera and Luzula.
Species in world 400, genera in world 8. Genera in study region: Juncus, Luzula.
Classification. Subclass Monocotyledonae. Dahlgren’s Superorder Commeliniflorae, Order Cyperales.
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).