Juncus tenuis |
Juncus mertensianus |
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path rush, poverty or slender rush, poverty rush, slender rush |
Mertens' rush |
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Habit | Herbs, perennial, tufted, 1.5–5 dm. | Herbs, perennial, rhizomatous to cespitose, 0.5–4 dm. |
Rhizomes | densely branching. |
1–2 mm diam., not swollen. |
Culms | few–20. |
erect, terete, 1–3 mm diam., smooth. |
Cataphylls | 0–1, straw-colored to chestnut brown, apex acute. |
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Leaves | basal, (1–)2–3; auricles 2–5 mm, apex acute, membranous; blade flat, 3–12 cm × 0.5–1 mm, margins entire. |
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 | 5–40-flowered, borne congested or branch internodes ca. as long as tepals, ssomewhat loose, 1–5 cm; primary bract usually longer than inflorescence. |
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 | bracteoles 2; tepals greenish, lanceolate, 3.3–4.4 mm; outer and inner series nearly equal; stamens 6, filaments 0.5–0.9 mm, anthers 0.1–0.2 mm; style 0.1–0.2 mm. |
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 | tan or light brown, 1-locular to pseudo-3-locular, ellipsoid, (3.3–)3.8–4.7 × (1.1–)1.3–1.7 mm, nearly equal to tepals. |
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 | tan, ellipsoid to lunate, (0.52–)5.5–0.65(–0.7) mm, not tailed. |
ellipsoid, 0.4–0.5 mm, not tailed; body clear yellow-brown. |
2n | = 80. |
= 40. |
Juncus tenuis |
Juncus mertensianus |
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Phenology | Flowering spring–early summer. | Fruiting mid summer–fall. |
Habitat | Exposed or shaded sites in soils ranging from sandy to clayey under moist or drier conditions, oftentimes these sites naturally or otherwise disturbed (e.g., game or human trails) | Montane to alpine meadows, stream banks, lake margins, and conifer woods |
Elevation | (400–)1900–3300 m ((1300–)6200–10800 ft) | |
Distribution |
AK; 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; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NS; ON; PE; QC; SK [Introduced worldwide]
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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 | Juncus tenuis occurs throughout North America. It is particularly abundant in northeastern United States and eastern Canada, although infrequent in the south and west. Through the use of isozyme electrophoresis, hybridization can be demonstrated between various members of the Juncus tenuis complex, including Juncus tenuis, J. anthelatus, J. interior, J. secundus, and J. dichotomus (R. E. Brooks, unpubl.). Juncus ××oronensis is thought to be a hybrid between J. tenuis and J. vaseyi in the northeast. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 22. | FNA vol. 22, p. 252. |
Parent taxa | Juncaceae > Juncus > subg. Poiophylli | Juncaceae > Juncus > subg. Septati |
Sibling taxa | ||
Synonyms | J. bicornis, J. bicornis var. williamsii, J. macer, J. macer, J. macer var. williamsii, J. tenuis var. bicornis, J. tenuis var. multicornis, J. tenuis var. williamsii | J. duranii, J. mertensianus var. duranii, J. mertensianus var. filifolius, J. slwookoorum |
Name authority | Willdenow: Sp. Pl. 2(1): 214. (1799) | Bongard: Mém. Acad. Imp. Sci. St.-Pétersbourg, Sér. 6, Sci. Math. 2: 167. (1833) |
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