Juncus dubius |
Juncus acuminatus |
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dubius rush, mariposa rush, questionable rush |
knotty-leaf rush, sharp-fruit rush, tapered rush, tapertip rush |
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Habit | Herbs, perennial, rhizomatous, 3–7.5 dm. | Herbs, perennial, cespitose, not rhizomatous, 1.4–10 dm. |
Rhizomes | 2–3 mm diam., not swollen. |
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Culms | erect, terete, 2–4 mm diam., smooth or rugulose. |
erect, terete, 1–3 mm diam., smooth. |
Cataphylls | 1–2, pink to straw-colored, apex acute. |
1–2, gray, apex acute. |
Leaves | basal 1–2, cauline 1–2; auricles 1–4.9 mm, , apex rounded, membranaceous; blade green to straw-colored, terete, 20–30 cm × 1.5–4 mm, rugulose or smooth. |
basal 1–2, cauline 1–2; auricles 1–1.5 mm, apex rounded, scarious; blade green, straw-colored, or pink, nearly terete, 1–40 cm. |
Inflorescences | terminal panicles of 25–66 heads, 7–13 cm, branches spreading; primary bract erect; heads 6–10-flowered, hemispheric to obovoid, 5–10 mm diam. |
terminal panicles of 5–50 heads, 5–15 cm, branches ascending; primary bract erect; heads (2–)5–20(–50)-flowered, hemispheric (to spheric), 3–10 mm diam. |
Flowers | tepals straw-colored to brown, lanceolate, apex acuminate; outer tepals (2–)2.5–3.4 mm; inner tepals (2–)2.6–3.6 mm; stamens 6, anthers 1.5–2 times filament length. |
tepals light brown to greenish, lanceolate, 2.6–3.5(–3.9) mm, apex acuminate; stamens 3 (or 6), anthers 1/3 filament length. |
Capsules | exserted, chestnut brown, 1-locular, subuloidsubulate, (2.4–)3–3.9 mm, apex tapering to subulate tip, valves separating at dehiscence. |
equaling perianth or slightly exserted, straw-colored, 1-locular, ellipsoid to narrowly ovoid, 2.8–3.5(–4) mm, apex acute, valves separating at dehiscence, fertile throughout or only proximal to middle. |
Seeds | obovoid, 0.3–0.4 mm, not tailed. |
ellipsoid to oblong, 0.3–0.4 mm, not tailed; body clear yellow-brown. |
2n | = 40. |
= 40. |
Juncus dubius |
Juncus acuminatus |
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Phenology | Fruiting early summer–late fall. | Fruiting early summer–fall. |
Habitat | Montane meadows, riverbeds, canyons, aroyos | Shores, swamps, ditches, springs, wet meadows, and rock outcrops |
Elevation | 100–1600 m (300–5200 ft) | 0–2200 m (0–7200 ft) |
Distribution |
CA
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AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; NE; NH; NJ; NM; NY; OH; OK; OR; PA; RI; SC; TN; TX; VA; VT; WA; WI; WV; BC; NS; ON; QC; Mexico; Central America (Honduras)
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Discussion | Juncus dubius has rugulose stems and leaves throughout most of its range, but on the periphery (in Mariposa, San Diego, and Sonoma counties, California) the plants are smooth. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 22. | FNA vol. 22. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | J. rugulosus | J. acuminatus var. legitimus, J. pallescens, J. pondii |
Name authority | Engelmann | Michaux: Flora Boreali-Americana 1: 192. (1803) |
Web links |
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