OregonFlora: Juncus canadensis vs. Juncus interior

	Juncus canadensis	Juncus interior
	Canada rush, Canadian rush	interior juncus
Habit	Plants perennial, 30–100 cm tall, cespitose.	Plants perennial, (11)20–60 cm tall, cespitose, base usually pink, 4–6 strong stem ridges visible per side.
Leaves	basal and cauline; round; hollow, septate, 1–2 mm wide; auricles 1–1.2 mm.	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	panicles of 3–50 clusters; clusters 5–50-flowered, not obscured by inflorescence bract.	cymes, 1.5– 7 cm; bractlets subtending flowers acuminate to aristate.
Flowers	tepals 6, green; reddish, or pale brown; tips acuminate; stamens 3; filaments 0.8–1.5 mm; anthers 0.3–0.5 mm; styles 0.2–0.3 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	usually 0–1 mm longer than the tepals, dark brown, 1-chambered.	3.3–4.7 mm; longer than the tepals, light brown; apex obtuse to truncate, not ridged or crested, 1-chambered.
Seeds	narrowly ellipsoid to linear, 1.25–1.9 × 0.2–0.25 mm; bodies 0.5– 0.8 mm; tails 0.3–0.5 mm, 0.5–1 times as long as seed body.	0.3–0.45 × 0.15–0.25 mm, apiculate.
2n	=80.	=80.

	Juncus canadensis	Juncus interior
Distribution	[WildflowerSearch map] [BONAP county map]	[WildflowerSearch map] [BONAP county map]
Discussion	Shores, ponds, peatlands, disturbed sandy acidic wet ground, cranberry farms, ditches. 0–100 m. Est. WA; north to British Columbia; eastern North America; Europe, New Zealand. Exotic. This species was introduced by cranberry agriculture and is spreading into natural wetlands. Some authors suggest rare flowers have 6 stamens.	River shores. 50–200 m. Col. CA, ID, WA; throughout North America. Native.
Source	Flora of Oregon, volume 1, page 273 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. 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 floras: BC, OR, WA 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 canadensis

Juncus interior

Canada rush, Canadian rush

interior juncus

Habit

Plants perennial, 30–100 cm tall, cespitose.

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

Leaves

basal and cauline; round; hollow, septate, 1–2 mm wide;

auricles 1–1.2 mm.

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

panicles of 3–50 clusters; clusters 5–50-flowered, not obscured by inflorescence bract.

cymes, 1.5– 7 cm;

bractlets subtending flowers acuminate to aristate.

Flowers

tepals 6, green; reddish, or pale brown;

tips acuminate;

stamens 3;

filaments 0.8–1.5 mm;

anthers 0.3–0.5 mm;

styles 0.2–0.3 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

usually 0–1 mm longer than the tepals, dark brown, 1-chambered.

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

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

Seeds

narrowly ellipsoid to linear, 1.25–1.9 × 0.2–0.25 mm;

bodies 0.5– 0.8 mm; tails 0.3–0.5 mm, 0.5–1 times as long as seed body.

0.3–0.45 × 0.15–0.25 mm, apiculate.

=80.

Juncus canadensis

Juncus interior

Distribution

[WildflowerSearch map]

[BONAP county map]

[WildflowerSearch map]

[BONAP county map]

Discussion

Shores, ponds, peatlands, disturbed sandy acidic wet ground, cranberry farms, ditches. 0–100 m. Est. WA; north to British Columbia; eastern North America; Europe, New Zealand. Exotic.

This species was introduced by cranberry agriculture and is spreading into natural wetlands. Some authors suggest rare flowers have 6 stamens.

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

Source

Flora of Oregon, volume 1, page 273
Peter Zika

Flora of Oregon, volume 1, page 279
Peter Zika

Sibling taxa