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black needle rush, blackgrass, blackgrass rush, Gerard's rush, saltmarsh rush, saltmeadow rush

dubius rush, mariposa rush, questionable rush

Habit Herbs, perennial, 2–9 dm. Herbs, perennial, rhizomatous, 3–7.5 dm.
Rhizomes

long- creeping.

2–3 mm diam., not swollen.

Culms

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

Cataphylls

1–3.

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

Leaves

basal, (1–)2–4;

auricles 0.4–0.6(–0.8) mm, scarious;

blade flat or somewhat channeled, 10–40 cm × 0.4–0.7 mm, margins entire.

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.

Inflorescences

10–30(–80)-flowered, usually loose and somewhat lax, 2–16 cm;

primary bract rarely surpassing inflorescence.

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.

Flowers

bracteoles 2;

tepals dark brown or blackish, lanceolate-ovate to oblong, 2.6–3.2(–3.8) mm;

inner and outer series nearly equal, apex obtuse;

stamens 6, filaments 0.4–0.7 mm, anthers 1.1–1.6(–1.8) mm;

style 0.4 mm.

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.

Capsules

chestnut brown or brown, 3-locular, widely ellipsoid, (2.2–)2.5–3.2(–3.5) × 1.3–1.9 mm.

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

Seeds

dark brown, ellipsoid to lunate, 0.485–0.6(–0.67) mm, not tailed.

obovoid, 0.3–0.4 mm, not tailed.

2n

= ca. 80, 84.

= 40.

Juncus gerardii

Juncus dubius

Phenology Flowering and fruiting late spring–summer. Fruiting early summer–late fall.
Habitat Forming extensive colonies in exposed coastal estuary meadows and salt marshes just above high- tide line, also inland Montane meadows, riverbeds, canyons, aroyos
Elevation 100–1600 m (300–5200 ft)
Distribution
from FNA
CO; CT; DE; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; MT; ND; NH; NJ; NY; OH; OR; OR; PA; RI; UT; VA; VT; WA; WI; BC; MB; NB; NF; NS; ON; PE; QC; SPM; Greenland; Europe; Asia
[WildflowerSearch map]
from FNA
CA
[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. Poiophylli 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. dubius, J. dudleyi, J. effusus, J. elliottii, J. ensifolius, J. falcatus, J. filiformis, J. filipendulus, J. georgianus, 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. 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. bulbosus var. gerardii, J. fucensis, J. gerardii var. pedicellatus J. rugulosus
Name authority Loiseleur-Deslongchamps: J. Bot. (Desvaux) 2: 284. (1809) Engelmann
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