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sharp rush, spiny rush

bulbous rush, spreading rush

Habit Herbs, perennial, cespitose, often with basal bulblike swellings, occasionally appearing rhizomatous, 0.3–3 dm, to 10 dm when floating or submersed.
Culms

erect or decumbent and rooting at nodes, or floating, terete, 1–2 mm diam., smooth.

Cataphylls

1, straw-colored, apex acute.

Leaves

basal 1, cauline 0–1;

auricles 0.4–1 mm, apex acute, scarious;

blade terete, occasionally filiform, flaccid, forming carpets, 2–10 cm × 0.8–1.4 mm.

Inflorescences

terminal racemes of 1–8(–30) heads, or single head, 2–10 cm, branches erect;

primary bract erect;

heads 2–6(–15)-flowered, obconic, 4.5–6.5 mm diam.

Flowers

often forming bulbils;

tepals pale brown, ovate to lanceolate or inner oblong, 2–3.6 mm, nearly equal, apex acute to obtuse;

stamens 3 or 6, anthers 3/4 to equal filament length.

Capsules

equaling perianth or exserted (to 0.5 mm beyond tepals), chestnut brown, 1-locular, cylindric, 2.5–4 mm, apex obtuse proximal to beak, valves separating at dehiscence.

Seeds

ellipsoid, 0.5–0.6 mm, not tailed;

body clear yellow-brown.

Juncus acutus

Juncus bulbosus

Phenology Fruiting mid summer–early fall.
Habitat Margins and siliceous or peaty shores of pools and streams, often floating
Elevation 0–200 m (0–700 ft)
Distribution
from FNA
AZ; CA; NV; South America; Mexico (Baja Calif); South Africa; Atlantic Islands
[WildflowerSearch map]
[BONAP county map]
from FNA
OR; WA; BC; NF; NS; SPM; Europe; n Africa [Probably introduced in North America]
[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. Septati
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. 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
Subordinate taxa
J. acutus subsp. leopoldii
Synonyms J. kockii, J. supinus
Name authority Linnaeus: Sp. Pl. 1: 325. (1753) Linnaeus: Sp. Pl. 1: 327. (1753)
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