FNA: Juncus acutiflorus vs. Juncus stygius

	Juncus acutiflorus	Juncus stygius
	sharpflower rush	bog rush, moor rush
Habit	Herbs, perennial, rhizomatous, to 8 dm.
Rhizomes	5–6 mm diam., nodes not swollen.
Culms	erect, terete, 3 mm diam., smooth.
Cataphylls	1, straw-colored, apex acute.
Leaves	basal 1, cauline 2; auricles 0.5 mm, apex rounded, cartilaginous; blade 7–45 cm x 1–2 mm, terete, not scabrous.
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.
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.
Capsules	inserted with beak exserted, straw-colored, 1-locular, narrowly ovoid, 2.3–2.4 mm, tapering to subulate tip, valves separating at dehiscence.
Seeds	narrowly ovoid, 0.5–0.6 mm, not tailed; body clear yellow-brown.

	Juncus acutiflorus	Juncus stygius
Phenology	Fruiting fall.
Habitat	Wet woods
Elevation	0–10 m (0–0 ft)
Distribution	NF; SPM; Europe; Asia; Africa [BONAP county map]	AK; ME; MI; MN; NY; AB; BC; MB; NB; NS; NT; NU; ON; PE; QC; SK; YT; Eurasia [WildflowerSearch map] [BONAP county map]
Discussion		Varieties 2 (1 in the flora). (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. 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. 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. stygius var. americanus
Name authority	Ehrhart: in G. F. Hoffmann, Deutschl. Fl. 1: 125. (1791)	Linnaeus: Syst. Nat. ed. 10 2: 987. (1759)
Web links	WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC Local Web sites: Go Botany, MI Flora, MN Wildflowers, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Juncus acutiflorus

Juncus stygius

sharpflower rush

bog rush, moor rush

Habit

Herbs, perennial, rhizomatous, to 8 dm.

Rhizomes

5–6 mm diam., nodes not swollen.

Culms

erect, terete, 3 mm diam., smooth.

Cataphylls

1, straw-colored, apex acute.

Leaves

basal 1, cauline 2;

auricles 0.5 mm, apex rounded, cartilaginous;

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

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.

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.

Capsules

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

Seeds

narrowly ovoid, 0.5–0.6 mm, not tailed;

body clear yellow-brown.

Juncus acutiflorus

Juncus stygius

Phenology

Fruiting fall.

Habitat

Wet woods

Elevation

0–10 m (0–0 ft)

Distribution

NF; SPM; Europe; Asia; Africa

[BONAP county map]

AK; ME; MI; MN; NY; AB; BC; MB; NB; NS; NT; NU; ON; PE; QC; SK; YT; Eurasia

[WildflowerSearch map]

[BONAP county map]

Discussion

Varieties 2 (1 in the flora).

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

Source

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. 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. 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. stygius var. americanus

Name authority

Ehrhart: in G. F. Hoffmann, Deutschl. Fl. 1: 125. (1791)

Linnaeus: Syst. Nat. ed. 10 2: 987. (1759)

Web links

Local floras: BC
Local Web sites: Go Botany, MI Flora, MN Wildflowers, PNW Herbaria
WildflowerSearch
iNaturalist (observations)
USDA Plants Database
LBJ Wildflower Center
SEINet
Plants of the World Online
Encyclopedia of Life
Wikipedia
Google Image Search

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).

Choose a data source: Flora of North America

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Flora of North America species comparison

Juncus acutiflorus

Juncus stygius

Juncus acutiflorus

Juncus stygius