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dubius rush, mariposa rush, questionable rush

Hall's rush

Habit Herbs, perennial, rhizomatous, 3–7.5 dm. Herbs, perennial, strongly tufted, to 4 dm.
Rhizomes

2–3 mm diam., not swollen.

densely short-branched.

Culms

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

terete.

Cataphylls

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

several.

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.

auricles 0.2 mm, apex acutish to rounded, scarious;

blade 4–15 cm.

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.

2–7-flowered, loose to congested;

primary bract usually longer than inflorescence.

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.

pedicellate;

bracteoles ovate;

tepals light brown with green midstripe, lanceolate or widely so, 4–5 mm, margins scarious;

inner series loosely subtending capsule at maturity, shorter;

stamens 6, filaments 0.8 mm, anthers 0.8–1.1 mm;

style 0.2 mm.

Capsules

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

brown, 3-locular, oblong-ovoid, 3.5–5 × 1.5–1.9 mm, slightly exceeding perianth.

Seeds

obovoid, 0.3–0.4 mm, not tailed.

amber, body 0.5 mm, tails 0.3 mm.

2n

= 40.

Juncus dubius

Juncus hallii

Phenology Fruiting early summer–late fall. Flowering and fruiting summer.
Habitat Montane meadows, riverbeds, canyons, aroyos Exposed slopes, stream banks, and meadows in montane and alpine areas
Elevation 100–1600 m (300–5200 ft) 1600–3000 m (5200–9800 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; ID; MT; UT; WA; WY
[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.)

Source FNA vol. 22. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Septati Juncaceae > Juncus > subg. Genuini
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. ensifolius, J. falcatus, J. filiformis, J. filipendulus, J. georgianus, J. gerardii, J. greenei, J. gymnocarpus, 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
Name authority Engelmann Engelmann
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