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three-flower rush, three-hulled rush

compressed rush, round-fruit rush

Habit Herbs, perennial, cespitose, 0.3–3.5 dm. Herbs, perennial, to 8 dm.
Rhizomes

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

Culms

1–8, 0.3–0.5 mm diam.

Cataphylls

1–2.

1–3.

Leaves

basal, 2–4;

auricles slightly prolonged, rounded, scarious to ± leathery;

blade deeply channeled, 2–10 cm, mostly shorter than culms.

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

solitary heads, each with 2–3(–50) flowers;

primary bracts brownish, nearly equal to or slightly shorter thanabout equaling inflorescence.

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

primary bract usually exceeding inflorescence.

Flowers

tepals pale brown or darker, oblong-lanceolate, 3–5 mm, outer and inner series nearly equal;

stamens 6, filaments 2.5–4 mm, anthers 0.6–1 mm;

styles 0.5–0.8 mm.

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

tan, pseudo-3-locular, 3-gonous–cylindric, apex obtuse, mucronate.

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

Seeds

tan or darker, fusiform, body 0.5–1 mm, tails 0.6–1 mm.

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

2n

= 44.

Juncus triglumis

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
AK; CO; ID; MT; NM; OR; UT; WY; AB; BC; MB; NT; NU; ON; QC; SK; YT; Eurasia
[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

Varieties 3 (2 in the flora).

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

Key
1. Most proximal bracts of inflorescence obtuse to mucronate, usually much shorter than inflorescence; capsules well exserted from perianth, 4.5–7 mm, apex conic or rounded proximal to persistent style
var. triglumis
1. Most proximal bracts of infloresecence equal to or longer than inflorescence, apex long acuminate or awned; capsules included or barely exserted from perianth, 3–5 mm, apex nearly truncate proximal to persistent style
var. albescens
Source FNA vol. 22. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Alpini Juncaceae > Juncus > subg. Poiophylli
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. 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. 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. triglumis var. albescens, J. triglumis var. triglumis
Synonyms J. bulbosus, J. supinus
Name authority Linnaeus: Sp. Pl. 1: 328. (1753) Jacquin: Enumeratio Stirpium Pleraumque, quae sponte crescung in agro Vindobonensi 60, 235. (1762)
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