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sharp rush, spiny rush

compressed rush, round-fruit rush

Habit Herbs, perennial, to 8 dm.
Rhizomes

short- creeping or densely branching, if densely branching herb appearing cespitose.

Cataphylls

1–3.

Leaves

basal and cauline, 1–2;

auricles 0.3–0.5 mm, scarious to membranous;

blade flat to slightly channeled, 5–35 cm × 0.8–2 mm, margins entire.

Inflorescences

5–60-flowered, lax, loose to moderately congested, 1.5–8 cm;

primary bract usually exceeding inflorescence.

Flowers

bracteoles 2;

tepals brownish, ovate to oblong, 1.7–2.7 mm;

inner and outer series nearly equal, apex obtuse;

stamens 6, filaments 0.5–0.7 mm, anthers 0.6–1 mm;

style 0.3 mm.

Capsules

brown or darker, pseudo-3-locular, widely ellipsoid to obovoid, 2.5–3.5 × 1.4–1.8 mm, exceeding tepals.

Seeds

light brown, ellipsoid to lunate, 0.35–0.556 mm, not tailed.

2n

= 44.

Juncus acutus

Juncus compressus

Phenology Flowering and fruiting late spring–early summer.
Habitat Disturbed ground, especially ditches, along railroads and banks of canals and roadsides, frequently in saline or alkaline soils
Elevation 1500–2100 m (4900–6900 ft)
Distribution
from FNA
AZ; CA; NV; South America; Mexico (Baja Calif); South Africa; Atlantic Islands
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; MD; ME; MI; MN; MT; ND; NE; NY; UT; WI; WY; MB; NF; NS; ON; QC; Europe; w Asia [Introduced in North America]
[WildflowerSearch map]
[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. Poiophylli
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. 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
Subordinate taxa
J. acutus subsp. leopoldii
Synonyms J. bulbosus, J. supinus
Name authority Linnaeus: Sp. Pl. 1: 325. (1753) Jacquin: Enumeratio Stirpium Pleraumque, quae sponte crescung in agro Vindobonensi 60, 235. (1762)
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