Juncus dubius |
Juncus polycephalus |
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dubius rush, mariposa rush, questionable rush |
flatleaf rush, manyhead rush |
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Habit | Herbs, perennial, rhizomatous, 3–7.5 dm. | Herbs, perennial, cespitose, 6–10 dm. |
Rhizomes | 2–3 mm diam., not swollen. |
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Culms | erect, terete, 2–4 mm diam., smooth or rugulose. |
erect, 3–14 mm diam. |
Cataphylls | 1–2, pink to straw-colored, apex acute. |
absent. |
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 2–3(–6), cauline 1–4, brownish green; auricles absent; blade 8–70 cm × 4–8 mm. |
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. |
panicles of 16–82 heads, 10–30 cm; primary bract erect; heads 20–30-flowered, spheric, 8–12 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 green to reddish, lance-subulate, 3–4 mm, nearly equal, apex acuminate; stamens 3, anthers 1/3–1/2 length of filaments. |
Capsules | exserted, chestnut brown, 1-locular, subuloidsubulate, (2.4–)3–3.9 mm, apex tapering to subulate tip, valves separating at dehiscence. |
exserted, straw-colored, 1-locular, narrowly ovoid, 4–5 mm, apex tapering to beak, remaining after dehiscence. |
Seeds | obovoid, 0.3–0.4 mm, not tailed. |
lance-ellipsoid, 0.5–0.6 mm, not tailed. |
2n | = 40. |
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Juncus dubius |
Juncus polycephalus |
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Phenology | Fruiting early summer–late fall. | Fruiting spring–fall. |
Habitat | Montane meadows, riverbeds, canyons, aroyos | Wet or seasonally wet shores, depressions, occasionally in fairly deep water of streams, usually with a peaty or mucky substrate, occasionally sandy to gravelly |
Elevation | 100–1600 m (300–5200 ft) | 0–100 m (0–300 ft) |
Distribution |
CA
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AL; FL; GA; LA; MD; MS; NC; SC; TX
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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. echinatus, J. engelmannii |
Name authority | Engelmann | Michaux: Flora Boreali-Americana 1: 192. 1803 (as polycephalos) |
Web links |