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weak rush

black needlerush, needle rush, needlegrass rush

Habit Herbs, perennial, cespitose, 1–2.5 dm. Herbs, perennial, 5–15 dm.
Rhizomes

long, thick, scaly.

Culms

erect, terete, 1–2 mm diam., smooth.

gray-green, 2–5 mm diam.

Cataphylls

0–1, maroon or dark green, apex acute.

2–5.

Leaves

basal 0–1, cauline 1–3;

auricles 1–1.5 mm, apex rounded, scarious;

blade maroon or dark green, terete, 1–12.5 cm × 0.5–1.5 mm.

basal, 1–3;

auricles absent;

blade terete, 40–80 cdm × 1.5–2.5 mm.

Inflorescences

terminal panicles of 3–50 heads, 2–8 cm, branches ascending to spreading;

primary bract erect;

heads 2–10-flowered, obpyramidal, 2–5 mm diam.

sympodial or appearing lateral, glomerules to 150, each with 2–6 perfect or pistillate flowers, congested to open, 4–20 × 5–10 cm;

primary bracts terete, longer than inflorescence.

Flowers

tepals green to straw-colored, lanceolate, 1.8–2.3(–2.5) mm, apex sharply acuminate;

stamens 3, 1/2 filament length.

tepals pale brown, 2.5–3.3 mm, apex acuminate;

outer series acuminate;

inner series slightly shorter, acutish;

stamens 6, sometimes rudimentary, filaments 0.2–0.7 mm, anthers 1.3–2.5 mm;

style 0.3–1 mm.

Capsules

exserted, straw-colored, 1-locular, narrowly ellipsoid to lanceoloid, 2.8–3.7 7(–4.2) mm, apex acute, valves separating at dehiscence.

brown, 3-locular, ovoid to oblate, 1.7–3 × 1.3–1.6 mm, mostly distinctly shorter than perianth, apiculate.

Seeds

ellipsoid, 0.3–0.4 mm, not tailed;

body clear yellow-brown.

dark brown, ellipsoid, 0.4–0.6 mm, not tailed.

Juncus debilis

Juncus roemerianus

Phenology Fruiting summer. Flowering and fruiting spring–early fall.
Habitat Marshy shores, in small streams, swamps, wet clearings, spring runs, commonly in very soft mucky substrates Coastal tidal marshes in dense zonal stands
Elevation 0–700 m (0–2300 ft)
Distribution
from FNA
AL; AR; DE; FL; GA; IL; KY; LA; MD; MO; MS; NC; NJ; NY; PA; SC; TN; TX; VA; Mexicos (Chiapas); Central America (Honduras)
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; DC; DE; FL; GA; LA; MD; MS; NC; SC; VA; Texas
[WildflowerSearch map]
[BONAP county map]
Discussion

Juncus debilis A. Gray is a name being proposed for conservation.

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

Source FNA vol. 22. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Septati Juncaceae > Juncus > subg. Juncus
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. 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. 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. 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. acuminatus var. debilis, J. radicans
Name authority A. Gray: Manual 481506. (1848) Scheele: Linnaea 22:348. (1849)
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