OregonFlora: Juncus tenuis vs. Juncus supiniformis

	Juncus tenuis	Juncus supiniformis
	path rush, poverty rush, slender rush	hair-leaved rush, spreading rush
Habit	Plants perennial, 15–50 cm tall, cespitose, usually delicate, base usually green to brown, with 0–1(2) strong longitudinal stem ridges visible on a side.	Plants perennial, 3–50 cm tall, cespitose, forming mats if submerged, sometimes stoloniferous with stems trailing and rooting at nodes.
Leaves	thin and wiry; blade flat and slightly inrolled, usually 1–8 mm on early season shoots; dirty white or translucent, scarious; acute or acuminate; auricles soft and thin.	numerous; capillary, 0.2– 0.3 mm wide if aquatic; round; hollow, septate; auricles 0.8–2.1 mm.
Inflorescences	cymes, usually small, 1–6 cm; individual flowers often longer than internodes; bractlets subtending flowers usually acute (blunt).	open, cymes of 2–9 clusters; clusters 2–5(12)-flowered, often bearing leafy bulblets.
Flowers	tepals 6, 3–4.1 mm, green to reddish; tips acuminate; stamens 6; filaments 0.6–1.2 mm; anthers usually 0.4–0.6(0.8)mm; styles 0.1–0.3(0.5)mm.	tepals 6, 3.4–5.4 mm, brown; greenish or reddish; inner tepal margins usually inrolled; tips acuminate; stamens 3 or 6; filaments 0.8–1.5 mm; anthers 0.5–0.8 mm; styles 0.1–0.4 mm.
Capsules	usually 2.5–3 mm; more than 75% the length of; and shorter than the tepals, pale brown; apex usually blunt (acute), not crested, 1-chambered.	usually 1–1.5 mm longer than the tepals, brown to dark brown; without metallic gloss, 1-chambered.
Seeds	0.4–0.5 × 0.2–0.25 mm, apiculate.	ellipsoid to ovoid, 0.6–1 × 0.2–0.3 mm, apiculate, striate.
2n	=40, 80.

	Juncus tenuis	Juncus supiniformis
Distribution	[WildflowerSearch map] [BONAP county map]	[WildflowerSearch map] [BONAP county map]
Discussion	Shores, swales, springs, dune hollows, wet woods, marshes, damp paths, ditches, cranberry farms, moist disturbed sites. 0–1800m. BW, Casc, CR, Est, Lava, Sisk, WV. CA, NV, ID, WA; throughout most of North America. Native. Juncus tenuis is usually much smaller than Juncus anthelatus. The blunt unridged capsules separate J. tenuis from J. confusus, J. occidentalis, and J. trilocularis.	Shores, peatlands, marshes, wet dune hollows, often in shallow water. 0–1100 m. Est, Casc. CA, WA, north to AK. Native. Like introduced Juncus bulbosus, this species can bear bulblets in the inflorescence, and both are variable in habit depending on water levels. They differ in the shape of the tepal tips and length of the capsules. Juncus articulatus is similar but has blunter tepal tips and is common on disturbed wet ground.
Source	Flora of Oregon, volume 1, page 284 Peter Zika	Flora of Oregon, volume 1, page 283 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. patens, J. pelocarpus, J. planifolius, J. ranarius, J. regelii, J. saximontanus, J. supiniformis, J. tiehmii, J. torreyi, J. triglumis, J. trilocularis, J. uncialis	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. patens, J. pelocarpus, J. planifolius, J. ranarius, J. regelii, J. saximontanus, J. tenuis, J. tiehmii, J. torreyi, J. triglumis, J. trilocularis, J. uncialis
Synonyms	Juncus tenuis var. tenuis	Juncus oreganus
Web links	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	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 supiniformis

path rush, poverty rush, slender rush

hair-leaved rush, spreading rush

Habit

Plants perennial, 15–50 cm tall, cespitose, usually delicate, base usually green to brown, with 0–1(2) strong longitudinal stem ridges visible on a side.

Plants perennial, 3–50 cm tall, cespitose, forming mats if submerged, sometimes stoloniferous with stems trailing and rooting at nodes.

Leaves

thin and wiry;

blade flat and slightly inrolled, usually 1–8 mm on early season shoots; dirty white or translucent, scarious; acute or acuminate;

auricles soft and thin.

numerous; capillary, 0.2– 0.3 mm wide if aquatic; round; hollow, septate;

auricles 0.8–2.1 mm.

Inflorescences

cymes, usually small, 1–6 cm; individual flowers often longer than internodes;

bractlets subtending flowers usually acute (blunt).

open, cymes of 2–9 clusters; clusters 2–5(12)-flowered, often bearing leafy bulblets.

Flowers

tepals 6, 3–4.1 mm, green to reddish;

tips acuminate;

stamens 6;

filaments 0.6–1.2 mm;

anthers usually 0.4–0.6(0.8)mm;

styles 0.1–0.3(0.5)mm.

tepals 6, 3.4–5.4 mm, brown; greenish or reddish;

inner tepal margins usually inrolled;

tips acuminate;

stamens 3 or 6;

filaments 0.8–1.5 mm;

anthers 0.5–0.8 mm;

styles 0.1–0.4 mm.

Capsules

usually 2.5–3 mm; more than 75% the length of; and shorter than the tepals, pale brown;

apex usually blunt (acute), not crested, 1-chambered.

usually 1–1.5 mm longer than the tepals, brown to dark brown; without metallic gloss, 1-chambered.

Seeds

0.4–0.5 × 0.2–0.25 mm, apiculate.

ellipsoid to ovoid, 0.6–1 × 0.2–0.3 mm, apiculate, striate.

=40, 80.

Juncus supiniformis

Distribution

[WildflowerSearch map]

[BONAP county map]

[WildflowerSearch map]

[BONAP county map]

Discussion

Shores, swales, springs, dune hollows, wet woods, marshes, damp paths, ditches, cranberry farms, moist disturbed sites. 0–1800m. BW, Casc, CR, Est, Lava, Sisk, WV. CA, NV, ID, WA; throughout most of North America. Native.

Juncus tenuis is usually much smaller than Juncus anthelatus. The blunt unridged capsules separate J. tenuis from J. confusus, J. occidentalis, and J. trilocularis.

Shores, peatlands, marshes, wet dune hollows, often in shallow water. 0–1100 m. Est, Casc. CA, WA, north to AK. Native.

Like introduced Juncus bulbosus, this species can bear bulblets in the inflorescence, and both are variable in habit depending on water levels. They differ in the shape of the tepal tips and length of the capsules. Juncus articulatus is similar but has blunter tepal tips and is common on disturbed wet ground.

Source

Flora of Oregon, volume 1, page 284
Peter Zika

Flora of Oregon, volume 1, page 283
Peter Zika

Sibling taxa