Juncus filiformis |
Juncus brevicaudatus |
|
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thread rush |
narrow-panicle rush, short-tail rush |
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Habit | Herbs, perennial, 0.2–3.5 dm. | Herbs, perennial, cespitose, 1.4–5.5(–7) dm. |
Rhizomes | widely creeping, sparingly branched, 1.5–2 mm diam., nodes closely set. |
|
Culms | terete, 1 mm diam. |
erect, terete, 1–3 mm diam., smooth. |
Cataphylls | several. |
0–1, straw-colored to pink, apex acute. |
Leaves | blade absent. |
basal 1–3, cauline 1–2; auricles 0.5–3 mm, apex rounded to truncate, scarious; blade terete, 1.5–25 cm × 0.5–2.5 mm. |
Inflorescences | 3–10(–12)-flowered, loosely congested, 1–2 cm; primary bract terete, nearly equaling to much longer than culm. |
terminal panicles or racemes of 2–35 heads, 1–12 cm, branches erect; primary bract erect; heads 2–8-flowered, ellipsoid to narrowly obconic, 2–9 mm diam. |
Flowers | pedicellate; bracteoles broadly ovate, tepals light brown or green, lanceolate, 2.5–4.2 mm; inner series loosely subtending capsule at maturity, slightly shorter, margins scarious; stamens 6, filaments 0.5–0.9 mm, anthers 0.5–0.7 mm; style 0.2 mm. |
tepals green to light brown, lanceolate; outer tepals 2.3–3.1 mm, apex acuminate to rarely obtuse; inner tepals 2.5–3.2 mm, apex acuminate; stamens 3 (or 6), anthers 1/4–1/2 filament length. |
Capsules | tan, 3-locular, nearly globose, 2.5–3 × 1.8–2.1 mm, shorter than perianth. |
exserted, chestnut brown, imperfectly 3-locular, narrowly ellipsoid to prismatic, 3.2–4.8 mm, apex acute proximal to beak, valves separating at dehiscence. |
Seeds | amber, 0.5–0.6 mm, not tailed. |
fusiform, 0.7–1.2 mm, tailed; body covered with whitish translucent veil. |
2n | = 40, 70, 80, 84. |
= 80. |
Juncus filiformis |
Juncus brevicaudatus |
|
Phenology | Flowering and fruiting summer. | Fruiting mid summer–fall. |
Habitat | Usually sandy, moist or wet soil along stream banks, pools, lakes or in meadow depressions, rarely in bogs, frequently hidden by larger vegetation | Generally in acidic or peaty moist sites, including emergent shorelines and aroundg hot springs |
Elevation | 0–3000 m (0–9800 ft) | 100–2500 m (300–8200 ft) |
Distribution |
AK; CO; ID; MA; ME; MI; MN; MT; NE; NH; NJ; NY; OR; PA; UT; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; SK; YT; SPM; Greenland; Eurasia; Atlantic Islands (Iceland)
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AZ; CO; CT; MA; MD; ME; MI; MN; MT; NC; NH; NY; OR; PA; RI; TN; UT; VA; VT; WI; WV; WY; AB; BC; MB; NB; NL; NS; ON; PE; QC; SK
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Discussion | Populations from about around hot springs in the west have been separated as Juncus tweedyi Rydberg, but no morphologic distinction appears to exist between J. tweedyi and J. brevicaudatus. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 22. | FNA vol. 22. |
Parent taxa | Juncaceae > Juncus > subg. Genuini | Juncaceae > Juncus > subg. Septati |
Sibling taxa | ||
Synonyms | J. canadensis var. brevicaudatus, J. canadensis var. coarctatus, J. canadensis var. kuntzei, J. coarctatus, J. kuntzei, J. tweedyi | |
Name authority | Linnaeus: Sp. Pl. 1: 326. (1753) | (Engelmann) Fernald: Rhodora 6: 35. (1904) |
Web links |