FNA: Juncus acutus vs. Juncus trifidus

	Juncus acutus	Juncus trifidus
	sharp rush, spiny rush	highland rush
Habit		Herbs, perennial, tufted, 1–4 dm.
Rhizomes		densely branching.
Culms		few to many, erect to drooping.
Cataphylls		2–4.
Leaves		basal and cauline, 2–4; auricles deeply lacerate, to 4 mm, membranous; blade dark green, flat to slightly channeled, 5–12 cm × 0.5–1 mm, margins finely serrulate.
Inflorescences		1–3(–4)-flowered; primary bract usually exceeding inflorescence.
Flowers		bracteoles 2, usually lacerate; tepals brownish, widely lanceolate, 2.1–3 mm; inner series slightly shorter, apex acute; stamens 6, filaments 0.3–0.7 mm, anthers 1.2–1.5 mm; stigma 1.5–3 mm.
Capsules		brown, ellipsoid, 2.2–3.5 × 1.3–1.7 mm, longer than tepals.
Seeds		brown, obliquely ovoid, 0.89–1.35 mm, not tailed.
2n		= 40.

	Juncus acutus	Juncus trifidus
Phenology		Flowering and fruiting late spring–early summer.
Habitat		Mostly in crevices of granitic (schistose) cliffs or rubble slopes in the higher regions of the Appalachians
Elevation		20–2000 m (100–6600 ft)
Distribution	AZ; CA; NV; South America; Mexico (Baja Calif); South Africa; Atlantic Islands [WildflowerSearch map] [BONAP county map]	ME; NC; NH; NY; TN; VA; VT; NB; NL; NS; QC; Greenland; Europe; n Asia [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. Poiophylli
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. 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. triformis, J. triglumis, J. trigonocarpus, J. uncialis, J. validus, J. vaseyi, J. xiphioides
Subordinate taxa	J. acutus subsp. leopoldii
Synonyms		J. monanthos, J. trifidus subsp. carolinianus, J. trifidus subsp. monanthos, J. trifidus var. monanthos
Name authority	Linnaeus: Sp. Pl. 1: 325. (1753)	Linnaeus: Sp. Pl. 1: 326. (1753)
Web links	Local Web sites: CalFlora, CalPhotos WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local Web sites: Go Botany WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Juncus acutus

Juncus trifidus

sharp rush, spiny rush

highland rush

Habit

Herbs, perennial, tufted, 1–4 dm.

Rhizomes

densely branching.

Culms

few to many, erect to drooping.

Cataphylls

2–4.

Leaves

basal and cauline, 2–4;

auricles deeply lacerate, to 4 mm, membranous;

blade dark green, flat to slightly channeled, 5–12 cm × 0.5–1 mm, margins finely serrulate.

Inflorescences

1–3(–4)-flowered;

primary bract usually exceeding inflorescence.

Flowers

bracteoles 2, usually lacerate;

tepals brownish, widely lanceolate, 2.1–3 mm;

inner series slightly shorter, apex acute;

stamens 6, filaments 0.3–0.7 mm, anthers 1.2–1.5 mm;

stigma 1.5–3 mm.

Capsules

brown, ellipsoid, 2.2–3.5 × 1.3–1.7 mm, longer than tepals.

Seeds

brown, obliquely ovoid, 0.89–1.35 mm, not tailed.

= 40.

Juncus acutus

Juncus trifidus

Phenology

Flowering and fruiting late spring–early summer.

Habitat

Mostly in crevices of granitic (schistose) cliffs or rubble slopes in the higher regions of the Appalachians

Elevation

20–2000 m (100–6600 ft)

Distribution

AZ; CA; NV; South America; Mexico (Baja Calif); South Africa; Atlantic Islands

[WildflowerSearch map]

[BONAP county map]

ME; NC; NH; NY; TN; VA; VT; NB; NL; NS; QC; Greenland; Europe; n Asia

[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. Poiophylli

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. 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. triformis, J. triglumis, J. trigonocarpus, J. uncialis, J. validus, J. vaseyi, J. xiphioides

Subordinate taxa

J. acutus subsp. leopoldii

Synonyms

J. monanthos, J. trifidus subsp. carolinianus, J. trifidus subsp. monanthos, J. trifidus var. monanthos

Name authority

Linnaeus: Sp. Pl. 1: 325. (1753)

Linnaeus: Sp. Pl. 1: 326. (1753)

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).

Choose a data source: Flora of North America

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Flora of North America species comparison

Juncus acutus

Juncus trifidus

Juncus acutus

Juncus trifidus