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dubius rush, mariposa rush, questionable rush

short-fruit rush, white-root rush

Habit Herbs, perennial, rhizomatous, 3–7.5 dm. Herbs, perennial, not cespitose, rhizomatous, (3–)4.5–8(–9) dm.
Rhizomes

2–3 mm diam., not swollen.

tuberous, 3–4 mm diam.

Culms

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

erect, terete, 2–3 mm diam., smooth.

Cataphylls

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

0(–1), straw-colored, 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 1–2, cauline 2–4, auricles 0.5–3.5 mm, apex rounded, scarious;

blade green to straw-colored, terete, 3–50 cm × 1–2 mm diam.

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 of 2–10(–20) heads or a single head, 1–4(–10) cm, branches ascending;

primary bract erect;

heads 30–100-flowered, spheric, 8–10 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 straw-colored, often red-tinted, lanceolate-subulate, apex acuminate;

outer tepals 2.5–3.8 mm;

inner tepals 2–3.2 mm;

stamens 3, 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.

included, chestnut brown, 1-locular, obconic or ovoid, 1.8–2.7 mm, apex obtuse, valves separating at dehiscence, fertile throughout or only proximal to middle.

Seeds

obovoid, 0.3–0.4 mm, not tailed.

ellipsoid to oblique-oblong, 0.3–0.4 mm, not tailed;

cody clear to yellow-brown.

2n

= 40.

= 44.

Juncus dubius

Juncus brachycarpus

Phenology Fruiting early summer–late fall. Fruiting mid summer–fall.
Habitat Montane meadows, riverbeds, canyons, aroyos Damp clayey, peaty, or sandy soils, swamps, ditches, ponds, wet woods, wet prairies
Elevation 100–1600 m (300–5200 ft) 0–500 m (0–1600 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CT; DE; FL; GA; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; MS; NC; NJ; NY; OH; OK; PA; SC; TN; TX; VA; WV; ON
[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.)

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. 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. 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
Name authority Engelmann Engelmann: in A. Gray, Manual of Botany of the Northern United States (ed. 5) 542. (1867)
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