OregonFlora: Juncus tenuis vs. Juncus regelii

	Juncus tenuis	Juncus regelii
	path rush, poverty rush, slender rush	Regel's 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, 15–60 cm tall, rhizomatous.
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.	flat; grass-like; less than 3 mm wide; auricles 0–1.6 mm.
Inflorescences	cymes, usually small, 1–6 cm; individual flowers often longer than internodes; bractlets subtending flowers usually acute (blunt).	1–5 clusters, usually head-like; clusters usually 10–30-flowered.
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, 4–6 × 1.1–1.6 mm, dark brown, papillose; inner usually shorter than or as long as the outer; stamens 6; filaments 0.8–1.3 mm; anthers 1–1.5 mm; style 1.1–2.8 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.	oblong-ovoid; shorter than the tepals, brown, obtuse or truncate, 3-chambered.
Seeds	0.4–0.5 × 0.2–0.25 mm, apiculate.	0.8–1.4(1.7) × 0.15–0.2 mm including tails; seed body 0.3–0.5 mm; seed tails (0.2)0.3–0.6 mm, 1 or both tails longer than the seed body.
2n	=40, 80.

	Juncus tenuis	Juncus regelii
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.	Wet meadows, swales, shores, seeps. 100–2600m. BR, BW, ECas, Lava, Casc. CA, NV, ID, WA; north to British Columbia, northeast to MT, southeast to WY. Native. This species is often confused with Juncus howellii, J. orthophyllus, and J. longistylis; the complex is sorted most reliably using seed characters; see the key.
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. saximontanus, J. supiniformis, J. tenuis, J. tiehmii, J. torreyi, J. triglumis, J. trilocularis, J. uncialis
Synonyms	Juncus tenuis var. tenuis
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 regelii

path rush, poverty rush, slender rush

Regel's 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, 15–60 cm tall, rhizomatous.

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.

flat; grass-like; less than 3 mm wide;

auricles 0–1.6 mm.

Inflorescences

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

bractlets subtending flowers usually acute (blunt).

1–5 clusters, usually head-like; clusters usually 10–30-flowered.

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, 4–6 × 1.1–1.6 mm, dark brown, papillose; inner usually shorter than or as long as the outer;

stamens 6;

filaments 0.8–1.3 mm;

anthers 1–1.5 mm;

style 1.1–2.8 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.

oblong-ovoid; shorter than the tepals, brown, obtuse or truncate, 3-chambered.

Seeds

0.4–0.5 × 0.2–0.25 mm, apiculate.

0.8–1.4(1.7) × 0.15–0.2 mm including tails;

seed body 0.3–0.5 mm;

seed tails (0.2)0.3–0.6 mm, 1 or both tails longer than the seed body.

=40, 80.

Juncus regelii

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.

Wet meadows, swales, shores, seeps. 100–2600m. BR, BW, ECas, Lava, Casc. CA, NV, ID, WA; north to British Columbia, northeast to MT, southeast to WY. Native.

This species is often confused with Juncus howellii, J. orthophyllus, and J. longistylis; the complex is sorted most reliably using seed characters; see the key.

Source

Flora of Oregon, volume 1, page 284
Peter Zika

Flora of Oregon, volume 1, page 283
Peter Zika

Sibling taxa