OregonFlora: Juncus patens

	Juncus patens
	gray rush, spreading rush
Habit	Plants perennial, 30–90 cm tall, cespitose, fresh stems ridged, dull, blue-green, with (8)10–15 prominent strong ridges visible per side when dried, pith of fertile stems solid.
Leaves	without blades; distal sheaths 4–10 cm, green to pale brown distally; dull or shiny; smooth; apex symmetrical; thin, not winged.
Inflorescences	a well-developed; loose cluster of 10–100+ flowers; branches usually visible; inflorescence bracts not swollen.
Flowers	tepals 6, green to pale brown; tips acute; stamens 6; filaments 0.5–1 mm; anthers 0.4–0.65 mm; styles 0.1 mm.
Capsules	subglobose, 2–2.7 mm, pale brown; apex rounded or subacute; styles deciduous or inconspicuous; capsule shorter than the tepals, 1-chambered.
Seeds	0.4–0.5 × 0.2–0.3 mm, apiculate.

	Juncus patens
Distribution	[WildflowerSearch map] [BONAP county map]
Discussion	Shores, floodplains, wet prairies, wet forest, swales, marshes, ditches. 0–1000 m. Casc, CR, Sisk, WV. CA, WA; south to Mexico. Native. The blue-green stems separate J. patens from all other cespitose species in Group 2, except the rare exotic J. inflexus, which has a chambered pith and dark tepals. However, the Australian introduction J. usitatus L.A.S. Johnson has become an invasive pest in northern California, where it has been mistakenly used in native plant restoration work and landscaping because it closely resembles J. patens. They are separable by the blunt not acute petals of J. usitatus, its three stamens per flower, and its tepals much shorter than the capsules. Juncus patens has six stamens per flower, and its tepals are longer than the capsules.
Source	Flora of Oregon, volume 1, page 282 Peter Zika
Sibling taxa	J. acuminatus, J. anthelatus, J. articulatus, J. balticus, J. bolanderi, J. brevicaudatus, J. breweri, J. bryoides, J. bufonius, J. bulbosus, J. canadensis, J. capillaris, J. capitatus, J. compressus, J. confusus, J. conglomeratus, J. covillei, J. diffusissimus, J. drummondii, J. dudleyi, J. effusus, J. ensifolius, J. ensifolius x Juncus nevadensis, J. exiguus, J. falcatus, J. filiformis, J. gerardi, J. hemiendytus, J. hesperius, J. howellii, J. inflexus, J. interior, J. kelloggii, J. laccatus, J. lescurii, J. longistylis, J. marginatus, J. mertensianus, J. mexicanus, J. nevadensis, J. occidentalis, J. orthophyllus, J. oxymeris, J. parryi, J. pelocarpus, J. planifolius, J. ranarius, J. regelii, J. saximontanus, J. supiniformis, J. tenuis, J. tiehmii, J. torreyi, J. triglumis, J. trilocularis, J. uncialis
Web links	Local floras: CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, 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 patens

gray rush, spreading rush

Habit

Plants perennial, 30–90 cm tall, cespitose, fresh stems ridged, dull, blue-green, with (8)10–15 prominent strong ridges visible per side when dried, pith of fertile stems solid.

Leaves

without blades;

distal sheaths 4–10 cm, green to pale brown distally; dull or shiny; smooth;

apex symmetrical; thin, not winged.

Inflorescences

a well-developed; loose cluster of 10–100+ flowers;

branches usually visible;

inflorescence bracts not swollen.

Flowers

tepals 6, green to pale brown;

tips acute;

stamens 6;

filaments 0.5–1 mm;

anthers 0.4–0.65 mm;

styles 0.1 mm.

Capsules

subglobose, 2–2.7 mm, pale brown;

apex rounded or subacute;

styles deciduous or inconspicuous; capsule shorter than the tepals, 1-chambered.

Seeds

0.4–0.5 × 0.2–0.3 mm, apiculate.

Juncus patens

Distribution

[WildflowerSearch map]

[BONAP county map]

Discussion

Shores, floodplains, wet prairies, wet forest, swales, marshes, ditches. 0–1000 m. Casc, CR, Sisk, WV. CA, WA; south to Mexico. Native.

The blue-green stems separate J. patens from all other cespitose species in Group 2, except the rare exotic J. inflexus, which has a chambered pith and dark tepals. However, the Australian introduction J. usitatus L.A.S. Johnson has become an invasive pest in northern California, where it has been mistakenly used in native plant restoration work and landscaping because it closely resembles J. patens. They are separable by the blunt not acute petals of J. usitatus, its three stamens per flower, and its tepals much shorter than the capsules. Juncus patens has six stamens per flower, and its tepals are longer than the capsules.

Source

Flora of Oregon, volume 1, page 282
Peter Zika

Sibling taxa

J. acuminatus, J. anthelatus, J. articulatus, J. balticus, J. bolanderi, J. brevicaudatus, J. breweri, J. bryoides, J. bufonius, J. bulbosus, J. canadensis, J. capillaris, J. capitatus, J. compressus, J. confusus, J. conglomeratus, J. covillei, J. diffusissimus, J. drummondii, J. dudleyi, J. effusus, J. ensifolius, J. ensifolius x Juncus nevadensis, J. exiguus, J. falcatus, J. filiformis, J. gerardi, J. hemiendytus, J. hesperius, J. howellii, J. inflexus, J. interior, J. kelloggii, J. laccatus, J. lescurii, J. longistylis, J. marginatus, J. mertensianus, J. mexicanus, J. nevadensis, J. occidentalis, J. orthophyllus, J. oxymeris, J. parryi, J. pelocarpus, J. planifolius, J. ranarius, J. regelii, J. saximontanus, J. supiniformis, J. tenuis, J. tiehmii, J. torreyi, J. triglumis, J. trilocularis, J. uncialis

Web links

Local floras: CA, OR, WA
Local Web sites: CalFlora, CalPhotos, Flora NW, 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 OregonFlora.

Choose a data source: Flora of North America, OregonFlora, UW Burke Herbarium

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Juncus patens

Juncus patens