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sharp rush, spiny rush

Cooper's rush

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

short.

Culms

terete, 1.5–2.5 mm diam.

Cataphylls

several, reddish brown, often apiculate.

Leaves

basal, 1–2;

auricles essentially absent;

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

Inflorescences

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

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

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

Juncus acutus

Juncus cooperi

Phenology Flowering and fruiting spring–summer.
Habitat Saline flats and meadows or edges of salt marshes
Elevation below 600 m (below 2000 ft)
Distribution
from FNA
AZ; CA; NV; South America; Mexico (Baja Calif); South Africa; Atlantic Islands
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NV; UT; Mexico
[BONAP county map]
Discussion

Subspecies 2 (1 in the flora).

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

Source FNA vol. 22, p. 237. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Juncus Juncaceae > Juncus > subg. Juncus
Sibling taxa
J. acuminatus, J. acutiflorus, 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. 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
Subordinate taxa
J. acutus subsp. leopoldii
Name authority Linnaeus: Sp. Pl. 1: 325. (1753) Engelmann
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