OregonFlora: Juncus acutus vs. Juncus interior

	Juncus acutus	Juncus interior
		interior juncus
Habit		Plants perennial, (11)20–60 cm tall, cespitose, base usually pink, 4–6 strong stem ridges visible per side.
Leaves		thin and wiry; blade flat and slightly inrolled; auricles soft, 2-textured, usually thicker proximally and more opaque than thin distal margin, 0.4–0.8(1.2)mm; dirty white to translucent; dull, rounded.
Inflorescences		cymes, 1.5– 7 cm; bractlets subtending flowers acuminate to aristate.
Flowers		tepals 6, light brown; tepal tips acuminate; stamens 6; filaments 0.8–1.1 mm; anthers 0.3–0.7(0.9) mm; styles 0.1–0.4(0.5)mm.
Capsules		3.3–4.7 mm; longer than the tepals, light brown; apex obtuse to truncate, not ridged or crested, 1-chambered.
Seeds		0.3–0.45 × 0.15–0.25 mm, apiculate.
2n		=80.

	Juncus acutus	Juncus interior
Distribution	[WildflowerSearch map] [BONAP county map]	[WildflowerSearch map] [BONAP county map]
Discussion		River shores. 50–200 m. Col. CA, ID, WA; throughout North America. Native.
Source		Flora of Oregon, volume 1, page 279 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. 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. 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
Web links	Local Web sites: 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 acutus

Juncus interior

interior juncus

Habit

Plants perennial, (11)20–60 cm tall, cespitose, base usually pink, 4–6 strong stem ridges visible per side.

Leaves

thin and wiry;

blade flat and slightly inrolled;

auricles soft, 2-textured, usually thicker proximally and more opaque than thin distal margin, 0.4–0.8(1.2)mm; dirty white to translucent; dull, rounded.

Inflorescences

cymes, 1.5– 7 cm;

bractlets subtending flowers acuminate to aristate.

Flowers

tepals 6, light brown;

tepal tips acuminate;

stamens 6;

filaments 0.8–1.1 mm;

anthers 0.3–0.7(0.9) mm;

styles 0.1–0.4(0.5)mm.

Capsules

3.3–4.7 mm; longer than the tepals, light brown;