Juncus alpinoarticulatus |
Juncus dichotomus |
|
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alpine rush, northern green rush, northern rush |
dichotomous rush, fork rush |
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Habit | Herbs, perennial, rhizomatous, 0.5–5 dm. | Herbs, perennial, to 10 dm. |
Rhizomes | 2–4 mm diam., not swollen. |
densely branched to short- creeping. |
Culms | erect, terete, 1–3 mm diam., smooth. |
|
Cataphylls | 0–1, straw-colored or maroon, apex acute. |
1–3. |
Leaves | basal 0–2, cauline 1–2(–5); auricles 0.5–1.2 mm, apex rounded, scarious; blade green to straw-colored, terete, 1.5–12 cm × 0.5–1.1 mm. |
basal, (1-)2-3; auricles 0.2-0.5(-0.6) mm, scarious to leathery; blade nearly terete, channeled or flat, 10-25(-40) cm × (0.5-)0.7-1(-1.2) mm, margins entire. |
Inflorescences | terminal panicles of 5–25 heads, 3–11 cm, branches erect to ascending; primary bract erect; heads 2–10-flowered, obpyramidal, usually with some flowers short- pedicellateled, 2–6 mm in diam. |
terminal, (5–)10–85(–100)-flowered, congested to somewhat loose, (1-)2.5-10(-13) cm; primary bract usually exceeding inflorescence. |
Flowers | tepals greenish to straw-colored, lanceolate to oblong; outer tepals 1.8–3 mm, apex obtuse, mucronate; inner tepals 1.6–2.7 mm, apex obtuse; stamens 6, anthers 1/2 filament length. |
bracteoles 2; tepals green, lanceolate, (3-)3.3-4.5(-5.5) mm; outer and inner series nearly equal; stamens 6, filaments 0.6–1.2 mm, anthers 0.4-0.8(-1) mm; style 0.2 mm. |
Capsules | equaling perianth to usually exserted, chestnut brown to straw-colored, imperfectly 3-locular, oblong to oblong-ovoid, 2.3–3.5 mm, apex obtuse, valves separating at dehiscence. |
tan to brown, 1-locular to pseudo-3-locular, ellipsoid to widely so, (2.5-)2.8-3.5(-4.5) × 1x 1.6-2.2 mm. |
Seeds | oblong to ovoid, 0.5–0.7 mm, not tailed. |
brownish to amber, ellipsoid to lunate, 0.3-0.4 mm, not tailed. |
2n | = 40. |
= ca. 80. |
Juncus alpinoarticulatus |
Juncus dichotomus |
|
Phenology | Fruiting mid summer–fall. | Flowering and fruiting late spring–summer. |
Habitat | Wet meadows, sandy and gravelly, often calcareous shores, fens, and clayey pools over rock | Ditches, shores, clearings, and other typically open areas, usually in sandy, well-drained (but frequently wet) soil |
Elevation | 0–2600 m (0–8500 ft) | |
Distribution |
AK; CO; IA; ID; IL; IN; ME; MI; MN; MO; MT; ND; NE; NY; OH; PA; SD; UT; VT; WA; WI; AB; BC; MB; NB; NL; NS; NT; ON; PE; QC; SK; YT; Greenland; ; Eurasia
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AL; AR; CO; CT; DC; DE; FL; GA; KY; LA; MA; MD; MS; NC; NJ; NY; OH; PA; RI; SC; TN; VA; WV; Mexico; Central America; South America; Texas
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Discussion | Several attempts have been made to separate subspecies or varieties of this widespread and variable species. In one study, five varieties were recognized, with four in North America (B. Lindquist 1932) . In another, at least six subspecies were recognized with two in North America (L. Hämet-Ahti 1986). The variation we.have encountered does not fit nicely into the subspecies Hämet-Ahti has recognized, and until a full account of the variation throughout the range of the species is presented, we are not recognizing subspecific or varietal divisions of this species. Recent evidence suggests that this species may be one of the parents of the tetraploid Juncus articulatus. Juncus alpinus hybridizes with J. brevicaudatus (= J. × gracilescens J. Hermann), J. articulatus (= J. × alpiniformis Fernald), J. nodosus (= J. × nodosiformis Fernald), and J. torreyi (= JuncusJ. ×stuckeyi Reinking). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 22, p. 254. | FNA vol. 22. |
Parent taxa | Juncaceae > Juncus > subg. Septati | Juncaceae > Juncus > subg. Poiophylli |
Sibling taxa | ||
Synonyms | J. alpinus, J.. alpinoarticulatus subsp. americanus, J.. alpinoarticulatus subsp. fuscescens, J.. alpinus var. americanus, J.. alpinus, J.. alpinus var. fuscescens, J.. alpinus var. insignis, J.. alpinus subsp. nodulosus, J.. alpinus var. rariflorus, J.. nodulosus, J.. rariflorus, J.. richardsonianus | J. dichotomus var. platyphyllus, J. tenuis var. dichotomus, J. tenuis var. platyphyllus, J. platyphyllus |
Name authority | Chaix: in D. Villars, Hist. Pl. Dauphiné 1: 378. (1786) | Elliott |
Web links |