Juncus articulatus |
Juncus longistylis |
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joint-leaf rush, jointed rush |
long-style rush |
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Habit | Herbs, perennial, rhizomatous to nearly cespitose, 0.5–6(–10) dm. | Herbs, perennial, 2–6 dm. |
Rhizomes | 2–3 mm diam., not swollen. |
long creeping. |
Culms | erect to decumbent (and floating), terete, 1–3 mm diam., smooth. |
slightly compressed. |
Cataphylls | 1, maroon to straw-colored, apex acute to obtuse. |
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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. |
basal 2–5, cauline 1–3; auricles 1–2.5 mm, apex truncate to obtuse; blade flat, 1–3 dm × 1.5–3 mm, the cauline shorter. |
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. |
glomerules 1–4(–8), each with 3–12 flowers, open or aggregate, 2–6(–10) cm; primary bract shorter than inflorescence. |
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. |
tepals brown with green midstripe, lanceolate, 5–6 mm, margins scarious, sometimes papillose; outer series slightly shorter; stamens 6, filaments 0.5–1 mm, anthers 1.2–2 mm; style 0.6 mm. |
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. |
tan, 3-locular, obovoid, 3–5 mm, shorter than perianth. |
Seeds | obovoid, 0.5 mm, not tailed. |
ovoid, 0.4–0.6 mm, not tailed. |
2n | = 80. |
= 40. |
Juncus articulatus |
Juncus longistylis |
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Phenology | Fruiting mid summer–fall. | Flowering and fruiting summer. |
Habitat | Wet ground in ditches, lake and stream margins, and a variety of other habitats, often a calciphile | Moist ground in mountain meadows |
Elevation | 0–3000 m (0–9800 ft) | 1000–3300 m (3300–10800 ft) |
Distribution |
AK; AZ; CA; CO; CT; ID; IN; KY; MA; ME; MI; MN; NC; NE; NH; NJ; NM; NV; NY; OH; OR; PA; RI; SD; UT; VA; VT; WA; WV; BC; NB; NF; NS; ON; PE; QC; SPM; Eurasia
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AZ; CA; CO; ID; MI; MN; MT; ND; NE; NM; NV; OR; SD; UT; WA; WY; AB; BC; MB; NF; ON; QC; SK
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Discussion | Juncus articulatus hybridizes with J. brevicaudatus (= 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. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 22. | FNA vol. 22. |
Parent taxa | Juncaceae > Juncus > subg. Septati | Juncaceae > Juncus > subg. Graminifolii |
Sibling taxa | ||
Synonyms | J. articulatus var. obtusatus, J. articulatus var. stolonifer, J. lampocarpus | |
Name authority | Linnaeus: Sp. Pl. 1: 327. (1753) | Torrey: in W. H. Emory, Report on the United States and Mexican Boundary Survey, ... 2(1): 223. (1859) |
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