OregonFlora: Juncus confusus vs. Juncus uncialis

	Juncus confusus	Juncus uncialis
	Colorado rush	inch-high rush, twelfth rush
Habit	Plants perennial, 20–50 cm tall, cespitose, stems with 0–5 strong ridges visible on one side.	Plants annual, 0.3–3.5 cm tall, unbranched, stems not thickened below flowers.
Leaves	thin and wiry; blade flat and slightly inrolled; auricles soft and thin distally, 0.3–0.8 mm; dull, rounded or acute; dirty white to translucent.	capillary; basal.
Inflorescences	cymes, 0.5–2.5 cm, usually dense and small.	1 terminal flower, subtended by solitary bractlet; base encircling stem; tip truncate.
Flowers	tepals 6, with broad medium brown stripes flanking a green midvein; tepal tips acuminate; erect; equal or subequal; stamens 6; filaments 0.7–1.1 mm; anthers 0.5–0.7 mm; styles 0.05–0.2 mm.	tepals usually 6 (4 or 8), green or reddish; stamens (2)3; filaments 0.9–1.6 mm; anthers 0.3–0.5 mm; styles 0.1–0.3 mm.
Capsules	2.5–3.5 mm; shorter than or equaling tepals, brown to dark brown; apex notched, crested, 3-chambered.	usually shorter than or equaling the tepals; (green) orange; reddish or dark purple and often darker than tepals.
Seeds	0.4–0.5 × 0.2–0.3 mm, apiculate, longitudinally ridged.	approximately 100–140 per capsule, 0.3–0.4 × 0.15–0.25 mm, sometimes faintly reticulate (at 10×), not striate.
2n	=80.	=32.

	Juncus confusus	Juncus uncialis
Distribution	[WildflowerSearch map] [BONAP county map]	[WildflowerSearch map] [BONAP county map]
Discussion	Seasonally moist or wet meadows, springs, swales, shores, ditches. 800–2700 m. BR, BW, ECas, Owy, Sisk. CA, NV, ID, WA; north to British Columbia, east to SD, southeast to NM. Native. This species is often confused with Juncus occidentalis, which shares the brown-striped tepals and crested capsules but does not grow east of the Cascades. Where they overlap in southwestern Oregon and California, they are separable by the internal structure of the capsules: three-chambered in J. confusus and one-chambered in J. occidentalis.	Vernal pools, shores exposed by receding water, stony swales. 50–2700m. BR, Col, ECas, Sisk. CA, NV, WA. Native.
Source	Flora of Oregon, volume 1, page 274 Peter Zika	Flora of Oregon, volume 1, page 284 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. 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	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. tenuis, J. tiehmii, J. torreyi, J. triglumis, J. trilocularis
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: 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 uncialis

Colorado rush

inch-high rush, twelfth rush

Habit

Plants perennial, 20–50 cm tall, cespitose, stems with 0–5 strong ridges visible on one side.

Plants annual, 0.3–3.5 cm tall, unbranched, stems not thickened below flowers.

Leaves

thin and wiry;

blade flat and slightly inrolled;

auricles soft and thin distally, 0.3–0.8 mm; dull, rounded or acute; dirty white to translucent.

capillary;

basal.

Inflorescences

cymes, 0.5–2.5 cm, usually dense and small.

1 terminal flower, subtended by solitary bractlet;

base encircling stem;

tip truncate.

Flowers

tepals 6, with broad medium brown stripes flanking a green midvein;

tepal tips acuminate; erect; equal or subequal;

stamens 6;

filaments 0.7–1.1 mm;

anthers 0.5–0.7 mm;

styles 0.05–0.2 mm.

tepals usually 6 (4 or 8), green or reddish;

stamens (2)3;

filaments 0.9–1.6 mm;

anthers 0.3–0.5 mm;

styles 0.1–0.3 mm.

Capsules

2.5–3.5 mm; shorter than or equaling tepals, brown to dark brown;

apex notched, crested, 3-chambered.

usually shorter than or equaling the tepals; (green) orange; reddish or dark purple and often darker than tepals.

Seeds

0.4–0.5 × 0.2–0.3 mm, apiculate, longitudinally ridged.

approximately 100–140 per capsule, 0.3–0.4 × 0.15–0.25 mm, sometimes faintly reticulate (at 10×), not striate.

=80.

=32.

Juncus uncialis

Distribution

[WildflowerSearch map]

[BONAP county map]

[WildflowerSearch map]

[BONAP county map]

Discussion

Seasonally moist or wet meadows, springs, swales, shores, ditches. 800–2700 m. BR, BW, ECas, Owy, Sisk. CA, NV, ID, WA; north to British Columbia, east to SD, southeast to NM. Native.

This species is often confused with Juncus occidentalis, which shares the brown-striped tepals and crested capsules but does not grow east of the Cascades. Where they overlap in southwestern Oregon and California, they are separable by the internal structure of the capsules: three-chambered in J. confusus and one-chambered in J. occidentalis.

Vernal pools, shores exposed by receding water, stony swales. 50–2700m. BR, Col, ECas, Sisk. CA, NV, WA. Native.

Source

Flora of Oregon, volume 1, page 274
Peter Zika

Flora of Oregon, volume 1, page 284
Peter Zika

Sibling taxa