Juncus dubius |
Juncus tiehmii |
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dubius rush, mariposa rush, questionable rush |
Nevada rush, Tiehm's dwarf rush, Tiehm's rush |
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Habit | Herbs, perennial, rhizomatous, 3–7.5 dm. | Herbs, annual, cespitose, 0.1–0.6 dm. |
Rhizomes | 2–3 mm diam., not swollen. |
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Culms | erect, terete, 2–4 mm diam., smooth or rugulose. |
to 150, 0.1–0.2 mm diam. |
Cataphylls | 1–2, pink to straw-colored, apex acute. |
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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. |
to 2.5 cm × 0.1–0.3 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. |
headlike clusters, each with 1–4(–7) flowers; bracts subtending inflorescence 2–4(–8), ovate, inconspicuous, 0.6–1.5 mm, membranous, apex acute. |
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. |
3-merous; : tepals 4(–6), green or darker, acute to acuminate, 1.9–2.9 × 0.4–0.6 mm, nearly equal; stamens 2(–3), filaments 0.5–0.8 mm, anthers 0.3–0.4 mm; style 0.2–0.3 mm, stigma 0.2–0.7 mm. |
Capsules | exserted, chestnut brown, 1-locular, subuloidsubulate, (2.4–)3–3.9 mm, apex tapering to subulate tip, valves separating at dehiscence. |
pink-tinged, 2- or 3-locular, ellipsoid to narrowly oblate, 1.9–2.9 × 1.1–1.5 mm, nearly equal or slightly longer than tepals. |
Seeds | obovoid, 0.3–0.4 mm, not tailed. |
oblate to ovoid, 0.35–0.55 mm. |
n | = 17. |
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2n | = 40. |
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Juncus dubius |
Juncus tiehmii |
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Phenology | Fruiting early summer–late fall. | Flowering and fruiting mid spring–early fall. |
Habitat | Montane meadows, riverbeds, canyons, aroyos | Bare, moist granitic sand along streams, seepage areas around outcrops, and depressions in meadows |
Elevation | 100–1600 m (300–5200 ft) | 300–3100 m (1000–10200 ft) |
Distribution |
CA
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CA; ID; NV; WA; Mexico |
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 | |
Name authority | Engelmann | Ertter: Memoirs of the New York Botanical Garden 39: 60, figs. 13f–g, 14. (1986) |
Web links |
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