Juncus uncialis |
Juncus articulatus |
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inch high dwarf rush, inch-high rush, twelfth rush |
joint-leaf rush, jointed rush |
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Habit | Herbs, annual, cespitose, 0.8–3.5 cm. | Herbs, perennial, rhizomatous to nearly cespitose, 0.5–6(–10) dm. |
Rhizomes | 2–3 mm diam., not swollen. |
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Culms | to 70, more than 0.2 mm diam.. |
erect to decumbent (and floating), terete, 1–3 mm diam., smooth. |
Cataphylls | 1, maroon to straw-colored, apex acute to obtuse. |
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Leaves | to 2.2 cm, 1/2–3/4 height of plant. |
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 solitary flowers; bracts subtending inflorescence 1, widely truncate, enwrapping culm, inconspicuous, 0.25–0.9 mm, membranous, apex widely truncate, completely sheathing culm.. |
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 | 3-merous, : tepals erect to recurved at maturity, greenish or tinged red, 2–4 × 0.6–0.9 mm; outer and inner series nearly equal, apex acutish; stamens usually 3, filaments 0.9–1.6 mm, anthers 0.3–0.4 mm, 1/3 length of filaments; style 0.1–0.3 mm, stigma 0.4–1.3 mm. |
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 | reddish to maroon, 3-locular, ovoid to ellipsoid, 1.8–3.2 × 1–2.5 mm, nearly equal or shorter than the tepals. |
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 | ovoid, 0.3–0.4 mm. |
obovoid, 0.5 mm, not tailed. |
n | = 16. |
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2n | = 80. |
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Juncus uncialis |
Juncus articulatus |
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Phenology | Flowering and fruiting spring–early summer. | Fruiting mid summer–fall. |
Habitat | Margins of vernal pools and ponds | Wet ground in ditches, lake and stream margins, and a variety of other habitats, often a calciphile |
Elevation | 0–1700 m (0–5600 ft) | 0–3000 m (0–9800 ft) |
Distribution |
CA; NV; OR
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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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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. Graminifolii | Juncaceae > Juncus > subg. Septati |
Sibling taxa | ||
Synonyms | J. articulatus var. obtusatus, J. articulatus var. stolonifer, J. lampocarpus | |
Name authority | Greene: Pittonia 2: 105. (1890) | Linnaeus: Sp. Pl. 1: 327. (1753) |
Web links |
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