Juncus L.
Bog rush.
Juncaceae, rush family.
Vegetative morphology. Plants perennial herbs; 3–50 cm high; caespitose, or not caespitose; with erect unbranched stems arising close together, or with stems growing in more or less straight rows. Ground-level or under-ground stems horizontal, 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. Sheaths with the margins fused only in the lower part, or with the margins not fused. Ligules absent. Blades 30–250 mm long; 0.3–4 mm wide. Blades straight; linear; with blade auricles, or without auricles; circular in cross section, or involute, or folded; veins parallel. Blades adaxial surface glabrous. Blades abaxial surface glabrous. Leaf apices acuminate.
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, or in inflorescences (usually). Inflorescence head-like; dense; 0.4–6 cm long. Pedicels absent. Flowers per inflorescence 1–10; small, less than 5 mm in diameter or length, or medium-sized, 5–15 mm in diameter or length. Floral bracts apex entire. 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; lanceolate; unlobed; 2.4–6.5 mm long. Stamens 6. Anthers 0.7–1.5 mm long. Gynoecia superior. Carpels syncarpous; 3. Styles 1. Stigmas per style 3. Ovules 10–100. 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 10–100; 0.4–3.5 mm long; brown; with surfaces smooth.
Chromosome information. 2n = 30, 60, 80, 84, 120, 130–134.
Distribution. Northern hemisphere distribution: Greenland, Canada.
Ecology and habitat. Habitats: Sp. Pl. 325.1753.
Notes. Represented in our area by five species.
Illustrations. • Juncus bufonius ssp. ranarius. Close-up. Entire plant. Note tepals not much longer than capsule. This is the native plant on northern seashores and lake shores. The more southern, ruderal ssp. bufonius has tepals much longer than capsule and very acute. Taxon to be expected in the Arctic Archipelago. Norway: Finnmark, Porsanger, Stuorranjarga. 30.07.1980. Photographed by R.Elven.
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).
