OregonFlora: Juncus hesperius vs. Juncus interior

	Juncus hesperius	Juncus interior
	bog rush, coast rush	interior juncus
Habit	Plants perennial, 30–100 cm tall, cespitose, fresh stems slightly dull, slightly ridged, slender, usually 0.8–1.9 mm diameter above distal sheath, with 5–14(18) strong ridges visible when dried.	Plants perennial, (11)20–60 cm tall, cespitose, base usually pink, 4–6 strong stem ridges visible per side.
Leaves	lacking blades; distal sheaths 4–20 cm, green (fresh) to pale or medium brown (dried); dull to slightly shiny, papillose; apex usually strongly asymmetrical on fruiting stems; thin, with broad membranous wings, flattened and lacking raised rims.	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	a loose to dense cluster; branches usually visible; inflorescence bracts not swollen; erect.	cymes, 1.5– 7 cm; bractlets subtending flowers acuminate to aristate.
Flowers	tepals 6, dark brown-striped; stamens 3; filaments 0.5–0.6 mm; anthers 0.5–0.8 mm; styles 0.05–0.1 mm.	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	2–2.7 mm; shorter than the tepals, brown to dark brown; apex acute to notched or obtuse, 1-chambered.	3.3–4.7 mm; longer than the tepals, light brown; apex obtuse to truncate, not ridged or crested, 1-chambered.
Seeds	0.4–0.5 × 0.2–0.25 mm, reticulate, apiculate.	0.3–0.45 × 0.15–0.25 mm, apiculate.
2n		=80.

	Juncus hesperius	Juncus interior
Distribution	[WildflowerSearch map] [BONAP county map]	[WildflowerSearch map] [BONAP county map]
Discussion	Shores, springs, swales, peatlands, wet pastures, cranberry farms, ditches. 0–800m. CR, Est, WV. CA, WA; north to British Columbia. Native. This species rarely hybridizes with J. laccatus. Montane J. exiguus has a symmetrical sheath apex and smooth sheath, differing from the more coastal J. hesperius, which has an asymmetrical sheath apex and papillose sheaths.	River shores. 50–200 m. Col. CA, ID, WA; throughout North America. Native.
Source	Flora of Oregon, volume 1, page 278 Peter Zika	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. 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 floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) 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 interior

bog rush, coast rush

interior juncus

Habit

Plants perennial, 30–100 cm tall, cespitose, fresh stems slightly dull, slightly ridged, slender, usually 0.8–1.9 mm diameter above distal sheath, with 5–14(18) strong ridges visible when dried.

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

Leaves

lacking blades;

distal sheaths 4–20 cm, green (fresh) to pale or medium brown (dried); dull to slightly shiny, papillose;

apex usually strongly asymmetrical on fruiting stems; thin, with broad membranous wings, flattened and lacking raised rims.

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

a loose to dense cluster;

branches usually visible;

inflorescence bracts not swollen; erect.

cymes, 1.5– 7 cm;

bractlets subtending flowers acuminate to aristate.

Flowers

tepals 6, dark brown-striped;

stamens 3;

filaments 0.5–0.6 mm;

anthers 0.5–0.8 mm;

styles 0.05–0.1 mm.

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

2–2.7 mm; shorter than the tepals, brown to dark brown;

apex acute to notched or obtuse, 1-chambered.

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

apex obtuse to truncate, not ridged or crested, 1-chambered.

Seeds

0.4–0.5 × 0.2–0.25 mm, reticulate, apiculate.

0.3–0.45 × 0.15–0.25 mm, apiculate.

=80.

Juncus interior

Distribution

[WildflowerSearch map]

[BONAP county map]

[WildflowerSearch map]

[BONAP county map]

Discussion

Shores, springs, swales, peatlands, wet pastures, cranberry farms, ditches. 0–800m. CR, Est, WV. CA, WA; north to British Columbia. Native.

This species rarely hybridizes with J. laccatus. Montane J. exiguus has a symmetrical sheath apex and smooth sheath, differing from the more coastal J. hesperius, which has an asymmetrical sheath apex and papillose sheaths.

River shores. 50–200 m. Col. CA, ID, WA; throughout North America. Native.

Source

Flora of Oregon, volume 1, page 278
Peter Zika

Flora of Oregon, volume 1, page 279
Peter Zika

Sibling taxa