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sharpflower rush

chestnut rush

Habit Herbs, perennial, rhizomatous, to 8 dm. Herbs, perennial, strongly rhizomatous, 1–4 dm.
Rhizomes

5–6 mm diam., nodes not swollen.

Culms

erect, terete, 3 mm diam., smooth.

solitary, 1–2 mm diam.

Cataphylls

1, straw-colored, apex acute.

1–2.

Leaves

basal 1, cauline 2;

auricles 0.5 mm, apex rounded, cartilaginous;

blade 7–45 cm x 1–2 mm, terete, not scabrous.

partially cauline, 3–5, auricles absent distally, rounded proximally;

blade channeled, to 20 cm, reduced distally.

Inflorescences

terminal panicles of 70–120 heads, 6–10 cm, branches ascending;

primary bract erect;

heads 3–5(–8)-flowered, obconic, 2–4 mm diam.

glomerules, 1–3(–5), each with 2–10 flowers;

peduncles 0.4–1.5 cm;

primary bracts somewhat inflated, usually surpassing inflorescence.

Flowers

tepals dark reddish brown, lanceolate, apex acuminate to subulate tipte;

outer tepals 1.9–2.2 mm;

inner tepals 2–2.3 mm;

stamens 6, anthers 2 times filament length.

bracteoles absent;

tepals brown or occasionally paler, lanceolate, 4.5–6.6 mm, apex acute to obtuse;

inner series slightly shorter;

stamens 6, filaments 2.5–3.5 mm, anthers 0.6–1.3 mm;

style 1–1.3 mm.

Capsules

inserted with beak exserted, straw-colored, 1-locular, narrowly ovoid, 2.3–2.4 mm, tapering to subulate tip, valves separating at dehiscence.

chestnut brown, 3-locular, narrowly oblong, 6.5–8.5 × 1.8–2.3 mm.

Seeds

narrowly ovoid, 0.5–0.6 mm, not tailed;

body clear yellow-brown.

pale yellow, fusiform, body 0.6–0.7 mm, tails 0.8–1.1 mm.

2n

= 60, 90, 120.

Juncus acutiflorus

Juncus castaneus

Phenology Fruiting fall. Flowering and fruiting late spring–summer.
Habitat Wet woods Tundra, subalpine and alpine bogs and meadows, and along streams in gravelly or clayey soils
Elevation 0–10 m (0–0 ft) 10–3700 m (0–12100 ft)
Distribution
from FNA
NF; SPM; Europe; Asia; Africa
[BONAP county map]
from FNA
AK; CO; MT; NM; NV; UT; WY; AB; BC; LB; MB; NT; NU; ON; QC; SK; YT; Greenland; Europe; Asia
[BONAP county map]
Discussion

In southern Alaska some plants with several many-flowered heads and capsules about double the length of the perianth have been referred to the Asian Juncus castaneus subsp. leucochlamys. The distinction, however, seems dubious without further investigation.

(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. Alpini
Sibling taxa
J. acuminatus, 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. 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. 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. castaneus var. pallidus, J. castaneus subsp. leucochlamys, J. leucochlamys
Name authority Ehrhart: in G. F. Hoffmann, Deutschl. Fl. 1: 125. (1791) Smith: Fl. Brit. 1: 383. (1800)
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