Flora of the Canadian Arctic Archipelago

DELTA Home

S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, L.J. Gillespie, A.K. Brysting, H. Solstad, and J.G. Harris

Juncaceae L.

French: Joncacées.

Juncaceae, Rush family.

Vegetative morphology. Plants 3–50 cm high; perennial herbs; caespitose, or not caespitose. Only fibrous roots present. Ground level or underground stems horizontal, or vertical, or absent; rhizomatous, or stoloniferous; elongate, or compact. Aerial stems erect. Leaves present, or absent or leaf teeth; merely cataphylls (Juncus arcticus); mainly basal, or distributed along the stems (absent in Juncus arcticus); alternate; dying annually and non-persistent, or marcescent. Petioles absent. Sheaths present; with the margins fused to the apex (or overlapping). Ligules absent. Leaves grass-like. Blades 10–250 mm long, 0.3–6 mm wide. Leaves not filiform (or not applicable). Blades straight, linear, with sheath auricles (slightly prolonged, scarious or slightly leathery, if applicable) or with clasping auricles or without auricles, veins parallel. Blade adaxial surface glabrous. Blade abaxial surface glabrous. Blade margins entire or serrulate (finely in Juncus trifidus), glabrous (Juncus) or scabrous (Luzula); apices acuminate (sometimes with calloused tips in Luzula).

Reproductive morphology. Flowering stems circular or oval in cross section. Flowering stems with leaves, or without leaves, or without leaves in the upper half. Leaf or reduced bract subtending the base of the inflorescence present; conspicuous and leaf-like, or reduced, or scale-like; exceeding the inflorescence, or similar in length to the inflorescence, or shorter than the apex of the inflorescence. Flowers solitary (rare), or in inflorescences (usually). Flower orientation flowers side by side in a horizontal plane, or two (or three) flowers side by side on one top of the other. Inflorescences paniculate, or cymose, or head-like; terminal; dense, or diffuse; 0.4–8 cm long. Pedicels present (short), or absent. Bisexual spike(s) with empty bracts at the base, or without empty bracts at the base. Floral bracts apices entire, or lacerate. Flowers per inflorescence 1–80; small, or medium-sized. Sepals conventional (brown tepals); 3; free; yellow, or brown; scarious; non-accrescent. Calyx tip mucronate, or tip not mucronate; glabrous. Petals conventional (brown tepals); 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(–2.2) mm long. Ovary superior; carpels 3; syncarpous. Styles 3; free. Stigmas per ovary 3. Ovules per ovary 3–100. Fruit sessile; with calyx persisting; dry; a capsule; ellipsoid, or ovoid, or elongate-cylindrical, or obovate; yellowish, or black, or brown; 2.5–7 mm long; 1–3 mm wide; not distinctly flattened; dehiscent. Styles persisting but not modified. Seeds 3–100; 0.4–3.5 mm long; brown; surfaces smooth.

Ecology and habitat. Substrates: wet meadows, hummocks, snow patches, around the margins of ponds, depressions of low-centre polygons, marshes, along streams, river terraces, lakeshores, tundra, slopes, ridges, cliffs, seashores.

North American distribution. Range in the Canadian Arctic Archipelago widespread, or limited. Common, uncommon, rare. Arctic, Low Arctic.

General notes. With two genera, Juncus and Luzula.

Illustrations. • Juncus bufonius subsp. albescens. Close-up of plant. This taxon is to be expected in the Arctic Archipelago. It is a native plant on northern seashores and lake shores. Note tepals not much longer than capsule. Norway, Finnmark, Porsanger, Stuorranjarga. 30 July, 1980. R. Elven.


This publication is available on the internet (posted May 2011) and on CD-ROM (published in 2007). These versions are identical in content, except that the errata page for CD-ROM is accessible on the main index page of the web version.

Recommended citation for the web-based version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada, Ottawa. http://nature.ca/aaflora/data, accessed on DATE.

Recommended citation for the CD-ROM version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. [CD-ROM] NRC Research Press, National Research Council of Canada, Ottawa.

.

Contents