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

two-flower rush, two-glumed rush

Habit Herbs, perennial, 2–9 dm. Herbs, perennial, loosely cespitose, 0.25–1.6 dm.
Rhizomes

long- creeping.

Culms

nearly terete.

Cataphylls

1–3.

2–4.

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, 1–4;

sheaths loose;

auricles absent or rounded, 0.5 mm;

blade imperfectly septate, ascending, nearly terete, 2–7 cm × 0.5–1.5 mm.

Inflorescences

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

primary bract rarely surpassing inflorescence.

heads, 1–2(–4)-flowered;

primary bracts much 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 brown to blackish, oblong, 2.5–4 mm, apex obtuse;

outer and inner series nearly equal;

stamens 6, filaments 1–1.5 mm, anthers 0.5–0.7 mm;

style deciduous, 0.3–0.4 mm.

Capsules

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

pale with dark purplish valve margins, pseudo-3-locular, oblate to narrowly ovoid, 4–5.5 × 1.7–2.3 mm, exceeding perianth, apex retuse.

Seeds

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

yellowish tan, fusiform-ovoid, 0.7–0.9 mm, short tailed.

2n

= ca. 80, 84.

= 120.

Juncus gerardii

Juncus biglumis

Phenology Flowering and fruiting late spring–summer. Flowering and fruiting summer.
Habitat Forming extensive colonies in exposed coastal estuary meadows and salt marshes just above high- tide line, also inland Wet tundra and mossy margins of ponds and streams, wet gravel and open, rocky slopes in alpine zones
Elevation 10–3400 m (0–11200 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
AK; CO; MT; WY; AB; BC; LB; MB; NT; NU; ON; QC; YT; Greenland; n Europe; Asia
[BONAP county map]
Source FNA vol. 22. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Poiophylli Juncaceae > Juncus > subg. Alpini
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. 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
Synonyms J. bulbosus var. gerardii, J. fucensis, J. gerardii var. pedicellatus
Name authority Loiseleur-Deslongchamps: J. Bot. (Desvaux) 2: 284. (1809) Linnaeus: Sp. Pl. 1: 328. (1753)
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