Juncus brachycephalus |
Juncus mertensianus |
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small-head rush |
Mertens' rush |
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Habit | Herbs, perennial, cespitose, 2–7 dm. | Herbs, perennial, rhizomatous to cespitose, 0.5–4 dm. |
Rhizomes | 1–2 mm diam., not swollen. |
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Culms | erect, 1–4 mm diam., smooth. |
erect, terete, 1–3 mm diam., smooth. |
Cataphylls | 1–2, straw-colored to pink, apex acute. |
0–1, straw-colored to chestnut brown, apex acute. |
Leaves | basal 1–3, cauline 1–2; auricles 0.6–1.5 mm, apex rounded, scarious; blade terete to compressed, 0.2–12 cm × 0.5–2 mm. |
basal 1–2, cauline 0–1; auricles 1–1.2 mm, apex rounded to acute, membranaceous or scarious; blade green to straw-colored, terete, 3–15 cm × 0.3–0.6 mm. |
Inflorescences | panicles of 5–80 heads, 5–25 cm, branches ascending; primary bract erect; heads 2–6-flowered, ellipsoid to obovoid, 2–5 mm diam. |
terminal single head (rarely cluster of 2 heads), 0.5–1.6 cm; primary bract erect; heads 12–60-flowered, spheric (to hemispheric), 4.5–15 mm diam. |
Flowers | tepals green to light brown, lanceolate; outer tepals 1.8–2.5 mm, apex obtuse to nearly acute; inner tepals 2–2.8 mm, apex obtuse to nearly acute; stamens 3 or 6, anthers 1/2 filament length. |
tepals dark purplish brown to black, lanceolate to lance-ovate, apex acute, mucro subulate; outer tepals 2.4–4.9 mm; inner tepals 2.3–4.3 mm; stamens 6, anthers 1/4 to equal filament length. |
Capsules | exserted, chestnut to dark brown, imperfectly 3-locular, obconic, 2.4–3.8 mm, apex acute proximal to beak, valves separating at dehiscence. |
included or slightly exserted, chestnut brown, 1-locular, obovoid, 1.9–3.5 mm, apex obtuse or rounded, valves separating at dehiscence, fertile throughout or only proximal to middle. |
Seeds | ellipsoid to fusiform, 0.8–1.2 mm, tailed; body covered with whitish translucent veil. |
ellipsoid, 0.4–0.5 mm, not tailed; body clear yellow-brown. |
2n | = 80. |
= 40. |
Juncus brachycephalus |
Juncus mertensianus |
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Phenology | Fruiting summer–early fall. | Fruiting mid summer–fall. |
Habitat | Calcareous marshes, wet meadows, and wetland shores | Montane to alpine meadows, stream banks, lake margins, and conifer woods |
Elevation | 100–200 m (300–700 ft) | (400–)1900–3300 m ((1300–)6200–10800 ft) |
Distribution |
AL; CO; CT; GA; IL; IN; MA; ME; MI; MN; NC; ND; NH; NJ; NY; OH; OK; PA; TN; VA; VT; WI; WV; NB; NS; ON; QC;
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AK; AZ; CA; CO; ID; MT; NM; NV; OR; UT; WA; WY; AB; BC; NT; SK; YT
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Discussion | Populations from southern California with brown tepals, anthers equaling filaments, and rounded to acute, translucent auricles have been separated as Juncus duranii; the typical form is so highly variable, however, that it can easily accommodate this local form. This species passes into Juncus nevadensis and has often been combined with that species (F. J. Hermann 1964). The two species can generally be separated, and we are following those treatments (F. J. Hermann 1975; A. Cronquist et al. 1972+, vol. 6). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 22. | FNA vol. 22, p. 252. |
Parent taxa | Juncaceae > Juncus > subg. Septati | Juncaceae > Juncus > subg. Septati |
Sibling taxa | ||
Synonyms | J. canadensis var. brachycephalus | J. duranii, J. mertensianus var. duranii, J. mertensianus var. filifolius, J. slwookoorum |
Name authority | (Engelmann) Buchenau: Botanische Jahrbucher fur Systematik, Pflanzengeschichte und Pflanzengeographie 12: 268. (1890) | Bongard: Mém. Acad. Imp. Sci. St.-Pétersbourg, Sér. 6, Sci. Math. 2: 167. (1833) |
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