OregonFlora: Juncus tenuis vs. Juncus ranarius

	Juncus tenuis	Juncus ranarius
	path rush, poverty rush, slender rush	frog 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 annual, 3–10(17)cm tall, branched.
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.	usually less than 1 mm wide; stem leaves usually 1–2.
Inflorescences	cymes, usually small, 1–6 cm; individual flowers often longer than internodes; bractlets subtending flowers usually acute (blunt).	cymose; flowers solitary at nodes.
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, green to light brown; outer tepals usually 4–5 mm; inner more or less blunt; stamens 6; filaments 0.7– 1.5 mm; anthers 0.4–0.8 mm; styles 0.3–0.4 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 truncate (blunt to subacute); (shorter than) more or less equaling inner tepals, brown, 1-chambered.
Seeds	0.4–0.5 × 0.2–0.25 mm, apiculate.	0.35–0.5 × 0.25–0.35 mm, apiculate.
2n	=40, 80.	=34.

	Juncus tenuis	Juncus ranarius
Distribution	[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.	Moist clay, stream banks, disturbed wet ground. 0–2000m. BR. CA; scattered across North America; North Africa, Eurasia. Exotic. Juncus ranarius is similar to J. bufonius, as well as Eurasian J. ambiguus, a misapplied name in our flora. The taxonomy of these species is controversial (Balslev 1996), and the complex needs worldwide revision. It is presumably exotic in North America and easily overlooked.
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. regelii, J. saximontanus, J. supiniformis, J. tenuis, J. tiehmii, J. torreyi, J. triglumis, J. trilocularis, J. uncialis
Synonyms	Juncus tenuis var. tenuis	Juncus ambiguus, Juncus bufonius var. halophilus
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 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 ranarius

path rush, poverty rush, slender rush

frog 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 annual, 3–10(17)cm tall, branched.

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.

usually less than 1 mm wide;

stem leaves usually 1–2.

Inflorescences

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

bractlets subtending flowers usually acute (blunt).

cymose;

flowers solitary at nodes.

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, green to light brown;

outer tepals usually 4–5 mm; inner more or less blunt;

stamens 6;

filaments 0.7– 1.5 mm;

anthers 0.4–0.8 mm;

styles 0.3–0.4 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 truncate (blunt to subacute); (shorter than) more or less equaling inner tepals, brown, 1-chambered.

Seeds

0.4–0.5 × 0.2–0.25 mm, apiculate.

0.35–0.5 × 0.25–0.35 mm, apiculate.

=40, 80.

=34.

Juncus ranarius

Distribution

[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.

Moist clay, stream banks, disturbed wet ground. 0–2000m. BR. CA; scattered across North America; North Africa, Eurasia. Exotic.

Juncus ranarius is similar to J. bufonius, as well as Eurasian J. ambiguus, a misapplied name in our flora. The taxonomy of these species is controversial (Balslev 1996), and the complex needs worldwide revision. It is presumably exotic in North America and easily overlooked.

Source

Flora of Oregon, volume 1, page 284
Peter Zika

Flora of Oregon, volume 1, page 283
Peter Zika

Sibling taxa