Juncus articulatus


Sp. Pl. 1: 327. 1753.

Common names: Jointed rush
Synonyms: Juncus articulatus var. obtusatus Engelmann Juncus articulatus var. stolonifer (Wohlleben) House Juncus lampocarpus
Treatment appears in FNA Volume 22.

Herbs, perennial, rhizomatous to nearly cespitose, 0.5–6(–10) dm. Rhizomes 2–3 mm diam., not swollen. Culms erect to decumbent (and floating), terete, 1–3 mm diam., smooth. Cataphylls 1, maroon to straw-colored, apex acute to obtuse. Leaves: basal 0–2, cauline (1–)3–6; auricles 0.5–1 mm, apex rounded, scarious; blade green to straw-colored, terete, 3.5–12 cm × 0.5–1.1 mm. Inflorescences terminal panicles of 3–30(–50) heads, 3.5–8 cm, branches spreading; primary bract erect; heads 3–10-flowered, obpyramidal to hemispheric, 6–8 mm diam. Flowers: tepals green to straw-colored or dark brown, ovate to lanceolate, 1.8–3 mm; outer tepals with apex acute or acuminate; inner tepals with apex acute acuminate to obtuse; stamens 6, anthers equal to filament length. Capsules exserted ca. 1 mm beyond perianth, chestnut brown to dark brown, imperfectly 3-locular, ellipsoid or ovoid, 2.8–4 mm, apex acute proximal to beak, valves separating at dehiscence. Seeds obovoid, 0.5 mm, not tailed. 2n = 80.

Phenology: Fruiting mid summer–fall.
Habitat: Wet ground in ditches, lake and stream margins, and a variety of other habitats, often a calciphile
Elevation: 0–3000 m


V22 209-distribution-map.jpg

St. Pierre and Miquelon, B.C., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., Que., P.E.I., Alaska, Ariz., Colo., Calif., Conn., Idaho, Ind., Ky., Maine, Mass., Mich., Minn., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., Ohio, Oreg., Pa., R.I., S.Dak., Utah, Vt., Va., Wash., W.Va., Eurasia.


Juncus articulatus hybridizes with J. tweedyi (= J. ×fulvescens Fernald), J. alpinus (= J. ×alpiniformis Fernald), J. nodosus, and J. canadensis.

Juncus articulatus var. obtusatus Engelmann appears to be intermediate with J. alpinus. It has spreading inflorescence branches but obtuse inner tepals. This may represent a backcross with J. alpinus. Recent evidence suggests that J. alpinus is a polyploid species with J. articulatus as one of its parents.

Selected References


Lower Taxa

... more about "Juncus articulatus"
Ralph E. Brooks* +  and Steven E. Clemants* +
Linnaeus +
Jointed rush +
St. Pierre and Miquelon +, B.C. +, N.B. +, Nfld. and Labr. (Nfld.) +, N.S. +, Ont. +, Que. +, P.E.I. +, Alaska +, Ariz. +, Colo. +, Calif. +, Conn. +, Idaho +, Ind. +, Ky. +, Maine +, Mass. +, Mich. +, Minn. +, Nebr. +, Nev. +, N.H. +, N.J. +, N.Mex. +, N.Y. +, N.C. +, Ohio +, Oreg. +, Pa. +, R.I. +, S.Dak. +, Utah +, Vt. +, Va. +, Wash. +, W.Va. +  and Eurasia. +
0–3000 m +
Wet ground in ditches, lake and stream margins, and a variety of other habitats, often a calciphile +
Fruiting mid summer–fall. +
Illustrated +
Juncus articulatus var. obtusatus +, Juncus articulatus var. stolonifer +  and Juncus lampocarpus +
Juncus articulatus +
Juncus subg. Septati +
species +