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

Cooper's rush

Habit Herbs, perennial, 2–9 dm. Herbs, perennial, robust, tufted, 4–10 dm.
Rhizomes

long- creeping.

short.

Culms

terete, 1.5–2.5 mm diam.

Cataphylls

1–3.

several, reddish brown, often apiculate.

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;

auricles essentially absent;

blade terete, 10–40 dcm, shorter than culm.

Inflorescences

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

primary bract rarely surpassing inflorescence.

glomerules 3–12, each with (1–)2–5 flowers, open, branches unequal, 3–12 cm, primary bract terete or slightly compressed, shorter to longer than inflorescence.

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 pale green, ovate-lanceolate, 4–5 mm, apex acuminate or setaceous;

inner series elliptic, nearly equal, margins wide, scarious, apiculate;

stamens 6, filaments 1 mm, anthers 1.5–2 mm;

style 1 mm.

Capsules

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

tan to light reddish brown, 3-locular, ellipsoid, 3.7–4.5 ×1.6–2 mm, mostly shorter than or nearly equal to perianth.

Seeds

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

dark amber, obovoid, body 0.7–1 mm, tails 0.1–0.5 mm.

2n

= ca. 80, 84.

Juncus gerardii

Juncus cooperi

Phenology Flowering and fruiting late spring–summer. Flowering and fruiting spring–summer.
Habitat Forming extensive colonies in exposed coastal estuary meadows and salt marshes just above high- tide line, also inland Saline flats and meadows or edges of salt marshes
Elevation below 600 m (below 2000 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
AZ; CA; NV; UT; Mexico
[BONAP county map]
Source FNA vol. 22. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Poiophylli Juncaceae > Juncus > subg. Juncus
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. 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. bulbosus var. gerardii, J. fucensis, J. gerardii var. pedicellatus
Name authority Loiseleur-Deslongchamps: J. Bot. (Desvaux) 2: 284. (1809) Engelmann
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