OregonFlora: Juncus diffusissimus vs. Juncus supiniformis

	Juncus diffusissimus	Juncus supiniformis
	slim pod rush	hair-leaved rush, spreading rush
Habit	Plants perennial, 25–65 cm tall, cespitose.	Plants perennial, 3–50 cm tall, cespitose, forming mats if submerged, sometimes stoloniferous with stems trailing and rooting at nodes.
Leaves	round; hollow, septate; auricles 1–3 mm.	numerous; capillary, 0.2– 0.3 mm wide if aquatic; round; hollow, septate; auricles 0.8–2.1 mm.
Inflorescences	open; clusters 20–70; clusters 2–5(10)-flowered.	open, cymes of 2–9 clusters; clusters 2–5(12)-flowered, often bearing leafy bulblets.
Flowers	tepals 6, 2–3.2 mm, green or pale brown; stamens 3; filaments 0.6–0.9 mm; anthers 0.4–0.5 mm; styles 0–0.1 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	4–5.2 mm, 0.5–2 mm longer than the tepals, pale brown or reddish, often with metallic or bronzy gloss, 1-chambered.	usually 1–1.5 mm longer than the tepals, brown to dark brown; without metallic gloss, 1-chambered.
Seeds	ellipsoid to ovoid, 0.3–0.4 × 0.2–0.3 mm, apiculate, reticulate.	ellipsoid to ovoid, 0.6–1 × 0.2–0.3 mm, apiculate, striate.

	Juncus diffusissimus	Juncus supiniformis
Distribution	[WildflowerSearch map] [BONAP county map]	[WildflowerSearch map] [BONAP county map]
Discussion	Moist river banks, wet disturbed gravel. 0–1000 m. Est. CA, WA; southeastern US; South America. Exotic.	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 275 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. 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. tenuis, J. tiehmii, J. torreyi, J. triglumis, J. trilocularis, J. uncialis
Synonyms		Juncus oreganus
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 supiniformis

slim pod rush

hair-leaved rush, spreading rush

Habit

Plants perennial, 25–65 cm tall, cespitose.

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

Leaves

round; hollow, septate;

auricles 1–3 mm.

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

auricles 0.8–2.1 mm.

Inflorescences

open; clusters 20–70; clusters 2–5(10)-flowered.

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

Flowers

tepals 6, 2–3.2 mm, green or pale brown;

stamens 3;

filaments 0.6–0.9 mm;

anthers 0.4–0.5 mm;

styles 0–0.1 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

4–5.2 mm, 0.5–2 mm longer than the tepals, pale brown or reddish, often with metallic or bronzy gloss, 1-chambered.

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

Seeds

ellipsoid to ovoid, 0.3–0.4 × 0.2–0.3 mm, apiculate, reticulate.

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

Juncus supiniformis

Distribution

[WildflowerSearch map]

[BONAP county map]

[WildflowerSearch map]

[BONAP county map]

Discussion

Moist river banks, wet disturbed gravel. 0–1000 m. Est. CA, WA; southeastern US; South America. Exotic.

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 275
Peter Zika

Flora of Oregon, volume 1, page 283
Peter Zika

Sibling taxa