Flora of North America species comparison

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Juncus acutus

Juncus megacephalus

sharp rush, spiny rush

bighead rush
Habit Herbs, perennial, rhizomatous, 3–11 dm.
Rhizomes

3–4 diam.
Culms

erect, terete, 3–4 mm diam., smooth.
Cataphylls

1–2, purple, apex acute.
Leaves

basal 0–1, cauline 2–3;

auricles 0.5–2 mm, apex acute, membranaceous;

blade terete, 0–24 cm × 0.5–1.7 mm, most distal cauline leaf blade 0–2 cm, shorter than sheath.
Inflorescences

panicles of (1–)3–21 heads, 1–8 cm, branches erect to spreading;

primary bract erect;

heads 40–60-flowered, spheric, 8–12 mm diam.
Flowers

tepals straw-colored to reddish brown, lanceolate-subulate;

outer tepals 2.9–4.1 mm, apex acuminate;

inner tepals 2.2–3.7 mm, apex acuminate;

stamens 3, anthers 1/4–1/2 filament length.
Capsules

exserted, , straw-colorerd, 1-locular, subulate, 2.5–4.2 mm, apex tapering to subulate beak, valves not separat ing at dehiscence, fertile throughout or only proximal to middle.
Seeds

ellipsoid to ovoid, 0.4 mm, not tailed;

body clear yellow-brown.

Juncus acutus

Juncus megacephalus
Phenology Fruiting summer.
Habitat Fresh marshes, moist hollows of sand dunes, swales, roadside ditches, and dry fertile soil
Elevation 0–100 m (0–300 ft)
Distribution
from FNA
AZ; CA; NV; South America; Mexico (Baja Calif); South Africa; Atlantic Islands
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA; LA; MD; MS; NC; SC; TX; VA
[WildflowerSearch map]
[BONAP county map]
Discussion

Subspecies 2 (1 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 22, p. 237. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Juncus Juncaceae > Juncus > subg. Septati
Sibling taxa
J. acuminatus, J. acutiflorus, 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. 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. 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. acutus subsp. leopoldii
Synonyms J. scirpoides var. carolinianus, J. scirpoides var. echinatus
Name authority Linnaeus: Sp. Pl. 1: 325. (1753) M. A. Curtis: Boston J. Nat. Hist. 1: 132. (1835)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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