OregonFlora: Juncus canadensis vs. Juncus laccatus

	Juncus canadensis	Juncus laccatus
	Canada rush, Canadian rush	shiny rush
Habit	Plants perennial, 30–100 cm tall, cespitose.	Plants perennial, 25–108 cm tall, cespitose, fresh stems shiny, smooth, dried fruiting stems slender, 0.6–2.6 mm diameter above distal sheath, remaining green, with 6–16 strong ridges becoming visible per side, dried ridges coarse or wide, capped with low dull cells.
Leaves	basal and cauline; round; hollow, septate, 1–2 mm wide; auricles 1–1.2 mm.	lacking blades; proximal sheaths smooth, not papillose (at 10×); distal sheaths 5–18 cm; distal half dark brown or black; shiny; thick and glossy; nerves obscure; apices symmetrical, unwinged, uniformly thick; dark, not inrolled.
Inflorescences	panicles of 3–50 clusters; clusters 5–50-flowered, not obscured by inflorescence bract.	loose clusters; branches usually visible; inflorescence bracts not swollen.
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; medium to dark brown-striped; stamens 3; filaments 0.4–0.9 mm; anthers 0.4–0.9 mm; styles 0.05–0.3 mm.
Capsules	usually 0–1 mm longer than the tepals, dark brown, 1-chambered.	1.7–2.2 mm; shorter than the tepals, brown to dark brown; apex obtuse to acute, 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.	0.4–0.6 × 0.2–0.25 mm, reticulate, apiculate.
2n	=80.	=40, 80.

	Juncus canadensis	Juncus laccatus
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.	Shores, swales, springs, seasonally wet ground, peatlands, and ditches. 0–1600m. Casc, CR, Est, WV. CA, WA; north to British Columbia, southeast to Arizona. Native. Occasionally cultivated, the thick shiny dark and smooth sheath of this species is distinctive; J. exiguus has a thinner, paler, and more textured sheath; J. hesperius has a less shiny, paler, and papillose sheath.
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. interior, J. kelloggii, 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
Synonyms		Juncus effusus var. gracilis
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) LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Juncus laccatus

Canada rush, Canadian rush

shiny rush

Habit

Plants perennial, 30–100 cm tall, cespitose.

Plants perennial, 25–108 cm tall, cespitose, fresh stems shiny, smooth, dried fruiting stems slender, 0.6–2.6 mm diameter above distal sheath, remaining green, with 6–16 strong ridges becoming visible per side, dried ridges coarse or wide, capped with low dull cells.

Leaves

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

auricles 1–1.2 mm.

lacking blades;

proximal sheaths smooth, not papillose (at 10×);

distal sheaths 5–18 cm;

distal half dark brown or black; shiny; thick and glossy; nerves obscure;

apices symmetrical, unwinged, uniformly thick; dark, not inrolled.

Inflorescences

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

loose clusters;

branches usually visible;

inflorescence bracts not swollen.

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; medium to dark brown-striped;

stamens 3;

filaments 0.4–0.9 mm;

anthers 0.4–0.9 mm;

styles 0.05–0.3 mm.

Capsules

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

1.7–2.2 mm; shorter than the tepals, brown to dark brown;

apex obtuse to acute, 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.

0.4–0.6 × 0.2–0.25 mm, reticulate, apiculate.

=80.

=40, 80.

Juncus canadensis

Juncus laccatus

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.

Shores, swales, springs, seasonally wet ground, peatlands, and ditches. 0–1600m. Casc, CR, Est, WV. CA, WA; north to British Columbia, southeast to Arizona. Native.

Occasionally cultivated, the thick shiny dark and smooth sheath of this species is distinctive; J. exiguus has a thinner, paler, and more textured sheath; J. hesperius has a less shiny, paler, and papillose sheath.

Source

Flora of Oregon, volume 1, page 273
Peter Zika

Flora of Oregon, volume 1, page 279
Peter Zika

Sibling taxa