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dubius rush, mariposa rush, questionable rush

dagger rush, dagger-leaf rush, sword-leaf rush, three-stamen rush

Habit Herbs, perennial, rhizomatous, 3–7.5 dm. Herbs, perennial, rhizomatous, 2–6 dm.
Rhizomes

2–3 mm diam., not swollen.

2–3 mm diam.

Culms

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

erect, 2–6 mm diam.

Cataphylls

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

0 or 1–2, straw-colored, apex narrowly 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 2–6, straw-colored;

auricles absent;

blade 2–25 cdm x 1.5–6 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.

panicles or racemes of 2–50 heads or heads solitary, 2–14 cm, erect or ascending branches;

primary bract erect;

heads 3–70-flowered, obovoid to globose, 7–11 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 brown or reddish brown, lanceolate;

outer tepals 2.7–3.6(–4) mm, apex acuminate;

inner tepals 2.2–3(–3.5) mm, nearly equal, apex acuminate;

stamens 3 or 6;

anthers ½1/2 to equal filament length.

Capsules

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

included to slightly exserted, chestnut to dark brown, 1-locular, oblong, 2.4–4.3 mm, apex obtuse proximal to beak.

Seeds

obovoid, 0.3–0.4 mm, not tailed.

elliptic to obovate, 0.4–1 mm, occasionally tailed.

2n

= 40.

Juncus dubius

Juncus ensifolius

Phenology Fruiting early summer–late fall.
Habitat Montane meadows, riverbeds, canyons, aroyos
Elevation 100–1600 m (300–5200 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; AZ; CA; CO; ID; MT; NM; NV; NY; OR; SD; TX; UT; WA; WI; WY; AB; BC; ON; QC; SK [Introduced in Europe and East Asia]
[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.)

Varieties 2 (2 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Stamens 3
var. ensifolius
1. Stamens 6
var. montanus
Source FNA vol. 22. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Septati Juncaceae > Juncus > subg. Ensifolii
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. 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. dubius, J. dudleyi, J. effusus, J. elliottii, 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
Subordinate taxa
J. ensifolius var. ensifolius, J. ensifolius var. montanus
Synonyms J. rugulosus
Name authority Engelmann Wikstrom: Kongl. Vetenskaps Academiens Handlingar 2: 274. (1823)
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