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small-head rush

thread rush

Habit Herbs, perennial, cespitose, 2–7 dm. Herbs, perennial, 0.2–3.5 dm.
Rhizomes

widely creeping, sparingly branched, 1.5–2 mm diam., nodes closely set.

Culms

erect, 1–4 mm diam., smooth.

terete, 1 mm diam.

Cataphylls

1–2, straw-colored to pink, apex acute.

several.

Leaves

basal 1–3, cauline 1–2;

auricles 0.6–1.5 mm, apex rounded, scarious;

blade terete to compressed, 0.2–12 cm × 0.5–2 mm.

blade absent.

Inflorescences

panicles of 5–80 heads, 5–25 cm, branches ascending;

primary bract erect;

heads 2–6-flowered, ellipsoid to obovoid, 2–5 mm diam.

3–10(–12)-flowered, loosely congested, 1–2 cm;

primary bract terete, nearly equaling to much longer than culm.

Flowers

tepals green to light brown, lanceolate;

outer tepals 1.8–2.5 mm, apex obtuse to nearly acute;

inner tepals 2–2.8 mm, apex obtuse to nearly acute;

stamens 3 or 6, anthers 1/2 filament length.

pedicellate;

bracteoles broadly ovate, tepals light brown or green, lanceolate, 2.5–4.2 mm;

inner series loosely subtending capsule at maturity, slightly shorter, margins scarious;

stamens 6, filaments 0.5–0.9 mm, anthers 0.5–0.7 mm;

style 0.2 mm.

Capsules

exserted, chestnut to dark brown, imperfectly 3-locular, obconic, 2.4–3.8 mm, apex acute proximal to beak, valves separating at dehiscence.

tan, 3-locular, nearly globose, 2.5–3 × 1.8–2.1 mm, shorter than perianth.

Seeds

ellipsoid to fusiform, 0.8–1.2 mm, tailed;

body covered with whitish translucent veil.

amber, 0.5–0.6 mm, not tailed.

2n

= 80.

= 40, 70, 80, 84.

Juncus brachycephalus

Juncus filiformis

Phenology Fruiting summer–early fall. Flowering and fruiting summer.
Habitat Calcareous marshes, wet meadows, and wetland shores Usually sandy, moist or wet soil along stream banks, pools, lakes or in meadow depressions, rarely in bogs, frequently hidden by larger vegetation
Elevation 100–200 m (300–700 ft) 0–3000 m (0–9800 ft)
Distribution
from FNA
AL; CO; CT; GA; IL; IN; MA; ME; MI; MN; NC; ND; NH; NJ; NY; OH; OK; PA; TN; VA; VT; WI; WV; NB; NS; ON; QC;
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; CO; ID; MA; ME; MI; MN; MT; NE; NH; NJ; NY; OR; PA; UT; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; SK; YT; SPM; Greenland; Eurasia; Atlantic Islands (Iceland)
[WildflowerSearch map]
[BONAP county map]
Source FNA vol. 22. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Septati Juncaceae > Juncus > subg. Genuini
Sibling taxa
J. acuminatus, J. acutiflorus, J. acutus, J. alpinoarticulatus, J. anthelatus, J. arcticus, J. articulatus, J. biglumis, J. bolanderi, J. brachycarpus, 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. 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. 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. canadensis var. brachycephalus
Name authority (Engelmann) Buchenau: Botanische Jahrbucher fur Systematik, Pflanzengeschichte und Pflanzengeographie 12: 268. (1890) Linnaeus: Sp. Pl. 1: 326. (1753)
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