OregonFlora: Juncus patens vs. Juncus breweri

	Juncus patens	Juncus breweri
	gray rush, spreading rush	Brewer's rush, salt 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.	Plants perennial, 20–140 cm tall, rhizomatous, stems usually flattened, often arching, twisted, without strong ridges visible fresh or dried.
Leaves	without blades; distal sheaths 4–10 cm, green to pale brown distally; dull or shiny; smooth; apex symmetrical; thin, not winged.	lacking blades; older distal sheaths 2–13 cm, dark brown; shiny; apex usually symmetrical; thin.
Inflorescences	a well-developed; loose cluster of 10–100+ flowers; branches usually visible; inflorescence bracts not swollen.	dense head-like clusters of 10–20 flowers; branches obscured.
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.	tepals 6, usually 6–8 mm, dark brown- or black-striped; stamens 6; filaments 0.4–0.7 mm; anthers 1.6–2.8 mm; styles 0.7–1.4 mm.
Capsules	subglobose, 2–2.7 mm, pale brown; apex rounded or subacute; styles deciduous or inconspicuous; capsule shorter than the tepals, 1-chambered.	3–5 mm; shorter than or equaling the tepals, dark brown; apex obtuse to acute, 3-chambered.
Seeds	0.4–0.5 × 0.2–0.3 mm, apiculate.	0.7–1.1 × 0.4–0.6 mm, not apiculate.

	Juncus patens	Juncus breweri
Distribution	[WildflowerSearch map] [BONAP county map]	[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.	Dunes, sandy swales, sandy ditches. 0–50 m. Est. CA, WA, north to British Columbia. Native. The little-known Juncus lescurii may represent a series of fertile hybrids between J. balticus and J. breweri and is intermediate in inflorescence characters. Juncus breweri has a denser and more nearly globose inflorescence than the other two taxa, with its inflorescence branches obscured by the compact arrangement of flowers or capsules.
Source	Flora of Oregon, volume 1, page 282 Peter Zika	Flora of Oregon, volume 1, page 272 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	J. acuminatus, J. anthelatus, J. articulatus, J. balticus, J. bolanderi, J. brevicaudatus, 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. patens, J. pelocarpus, J. planifolius, J. ranarius, J. regelii, J. saximontanus, J. supiniformis, J. tenuis, J. tiehmii, J. torreyi, J. triglumis, J. trilocularis, J. uncialis
Synonyms		Juncus arcticus, Juncus arcticus var. balticus
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	Local floras: BC, 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 breweri

gray rush, spreading rush

Brewer's rush, salt 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.

Plants perennial, 20–140 cm tall, rhizomatous, stems usually flattened, often arching, twisted, without strong ridges visible fresh or dried.

Leaves

without blades;

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

apex symmetrical; thin, not winged.

lacking blades; older distal sheaths 2–13 cm, dark brown; shiny;

apex usually symmetrical; thin.

Inflorescences

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

branches usually visible;

inflorescence bracts not swollen.

dense head-like clusters of 10–20 flowers;

branches obscured.

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.

tepals 6, usually 6–8 mm, dark brown- or black-striped;

stamens 6;

filaments 0.4–0.7 mm;

anthers 1.6–2.8 mm;

styles 0.7–1.4 mm.

Capsules

subglobose, 2–2.7 mm, pale brown;

apex rounded or subacute;

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

3–5 mm; shorter than or equaling the tepals, dark brown;

apex obtuse to acute, 3-chambered.

Seeds

0.4–0.5 × 0.2–0.3 mm, apiculate.

0.7–1.1 × 0.4–0.6 mm, not apiculate.

Juncus breweri

Distribution

[WildflowerSearch map]

[BONAP county map]

[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.

Dunes, sandy swales, sandy ditches. 0–50 m. Est. CA, WA, north to British Columbia. Native.

The little-known Juncus lescurii may represent a series of fertile hybrids between J. balticus and J. breweri and is intermediate in inflorescence characters. Juncus breweri has a denser and more nearly globose inflorescence than the other two taxa, with its inflorescence branches obscured by the compact arrangement of flowers or capsules.

Source

Flora of Oregon, volume 1, page 282
Peter Zika

Flora of Oregon, volume 1, page 272
Peter Zika

Sibling taxa