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dubius rush, mariposa rush, questionable rush

narrow-panicle rush, short-tail rush

Habit Herbs, perennial, rhizomatous, 3–7.5 dm. Herbs, perennial, cespitose, 1.4–5.5(–7) dm.
Rhizomes

2–3 mm diam., not swollen.

Culms

erect, terete, 2–4 mm diam., smooth or rugulose.

erect, terete, 1–3 mm diam., smooth.

Cataphylls

1–2, pink to straw-colored, apex acute.

0–1, straw-colored to pink, apex acute.

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.

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

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.

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

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.

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

exserted, chestnut brown, 1-locular, subuloidsubulate, (2.4–)3–3.9 mm, apex tapering to subulate tip, valves separating at dehiscence.

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

obovoid, 0.3–0.4 mm, not tailed.

fusiform, 0.7–1.2 mm, tailed;

body covered with whitish translucent veil.

2n

= 40.

= 80.

Juncus dubius

Juncus brevicaudatus

Phenology Fruiting early summer–late fall. Fruiting mid summer–fall.
Habitat Montane meadows, riverbeds, canyons, aroyos Generally in acidic or peaty moist sites, including emergent shorelines and aroundg hot springs
Elevation 100–1600 m (300–5200 ft) 100–2500 m (300–8200 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
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
[WildflowerSearch map]
[BONAP county map]
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.)

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.)

Source FNA vol. 22. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Septati Juncaceae > Juncus > subg. Septati
Sibling taxa
J. acuminatus, J. acutiflorus, J. acutus, J. alpinoarticulatus, J. anthelatus, J. arcticus, J. articulatus, J. biglumis, J. bolanderi, J. brachycarpus, J. brachycephalus, J. brachyphyllus, J. brevicaudatus, J. bryoides, J. bufonius, J. bulbosus, J. caesariensis, J. canadensis, J. capillaris, J. capitatus, J. castaneus, J. chlorocephalus, J. compressus, J. confusus, J. cooperi, J. coriaceus, J. covillei, J. debilis, J. dichotomus, J. diffusissimus, J. drummondii, J. dudleyi, J. effusus, J. elliottii, J. ensifolius, J. falcatus, J. filiformis, J. filipendulus, J. georgianus, J. gerardii, J. greenei, J. gymnocarpus, J. hallii, J. hemiendytus, J. howellii, J. inflexus, J. interior, J. kelloggii, J. leiospermus, J. lesueurii, J. longistylis, J. luciensis, J. macrandrus, J. macrophyllus, J. marginatus, J. maritimus, J. megacephalus, J. mertensianus, J. militaris, J. nevadensis, J. nodatus, J. nodosus, J. occidentalis, J. orthophyllus, J. oxymeris, J. parryi, J. patens, J. pelocarpus, J. pervetus, J. phaeocephalus, J. polycephalus, J. regelii, J. repens, J. roemerianus, J. scirpoides, J. secundus, J. squarrosus, J. stygius, J. subcaudatus, J. subtilis, J. supiniformis, J. tenuis, J. texanus, J. textilis, J. tiehmii, J. torreyi, J. trifidus, J. triformis, J. triglumis, J. trigonocarpus, J. uncialis, J. validus, J. vaseyi, J. xiphioides
J. acuminatus, J. acutiflorus, J. acutus, J. alpinoarticulatus, J. anthelatus, J. arcticus, J. articulatus, J. biglumis, J. bolanderi, J. brachycarpus, J. brachycephalus, J. brachyphyllus, J. bryoides, J. bufonius, J. bulbosus, J. caesariensis, J. canadensis, J. capillaris, J. capitatus, J. castaneus, J. chlorocephalus, J. compressus, J. confusus, J. cooperi, J. coriaceus, J. covillei, J. debilis, J. dichotomus, J. diffusissimus, J. drummondii, J. dubius, J. dudleyi, J. effusus, J. elliottii, J. ensifolius, J. falcatus, J. filiformis, J. filipendulus, J. georgianus, J. gerardii, J. greenei, J. gymnocarpus, J. hallii, J. hemiendytus, J. howellii, J. inflexus, J. interior, J. kelloggii, J. leiospermus, J. lesueurii, J. longistylis, J. luciensis, J. macrandrus, J. macrophyllus, J. marginatus, J. maritimus, J. megacephalus, J. mertensianus, J. militaris, J. nevadensis, J. nodatus, J. nodosus, J. occidentalis, J. orthophyllus, J. oxymeris, J. parryi, J. patens, J. pelocarpus, J. pervetus, J. phaeocephalus, J. polycephalus, J. regelii, J. repens, J. roemerianus, J. scirpoides, J. secundus, J. squarrosus, J. stygius, J. subcaudatus, J. subtilis, J. supiniformis, J. tenuis, J. texanus, J. textilis, J. tiehmii, J. torreyi, J. trifidus, J. triformis, J. triglumis, J. trigonocarpus, J. uncialis, J. validus, J. vaseyi, J. xiphioides
Synonyms J. rugulosus J. canadensis var. brevicaudatus, J. canadensis var. coarctatus, J. canadensis var. kuntzei, J. coarctatus, J. kuntzei, J. tweedyi
Name authority Engelmann (Engelmann) Fernald: Rhodora 6: 35. (1904)
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