Burke: Equisetum palustre vs. Equisetum laevigatum

	Equisetum palustre	Equisetum laevigatum
	marsh horsetail	smooth scouring rush
Habit	Rhizomatous annual, the stems not dimorphic, 2-8 dm. tall, with 5 to 10 deep grooves, the ridges smooth; stomates in a single, broad band in each furrow; central cavity less than 1/3 the diameter of the stem; sheathes green, 5-10 mm. long, with persistent teeth 3-7 mm. long, black or dark brown with broad, pale, papery margins.	Rhizomatous perennial with stems lasting less than a year, sometimes overwintering in southwestern United States, typically unbranched, 2-15 dm. tall, with single lines of stomates and 10-32 ridges; sheaths green and elongate, 7-15 mm long and 3-9 mm bread; teeth 10-32, articulate and typically shedding early with dark rim on sheath remaining.
Leaves	Branches few and irregular to many and whorled, 5- to 6-angled, simple.	None
Spores	Cones pedunculate, blunt, deciduous.	Cone tip rounded; spores green and spheric.

	Equisetum palustre	Equisetum laevigatum
Habitat	Streambanks, wet meadows, and marshes, from the lowlands to moderate elevations in the mountains.	Wet places, including meadows and streambanks, at low to middle elevations.
Distribution	Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across the northern U.S. and Canada to the Atlantic Coast; circumboreal. [WildflowerSearch map] [BONAP county map]	Occurring chiefly east of the Cascades crest in Washngton; southern British Columbia to California, east to the Rocky Mountains, Great Plains, Great Lakes region, and northeastern North America. [WildflowerSearch map] [BONAP county map]
Origin	Native	Native
Conservation status	Not of concern	Not of concern
Sibling taxa	E. arvense, E. ×ferrissii, E. fluviatile, E. hyemale, E. laevigatum, E. ×litorale, E. ×mackaii, E. ×nelsonii, E. scirpoides, E. sylvaticum, E. telmateia, E. variegatum	E. arvense, E. ×ferrissii, E. fluviatile, E. hyemale, E. ×litorale, E. ×mackaii, E. ×nelsonii, E. palustre, E. scirpoides, E. sylvaticum, E. telmateia, E. variegatum
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: 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

Equisetum laevigatum

marsh horsetail

smooth scouring rush

Habit

Rhizomatous annual, the stems not dimorphic, 2-8 dm. tall, with 5 to 10 deep grooves, the ridges smooth; stomates in a single, broad band in each furrow; central cavity less than 1/3 the diameter of the stem; sheathes green, 5-10 mm. long, with persistent teeth 3-7 mm. long, black or dark brown with broad, pale, papery margins.

Rhizomatous perennial with stems lasting less than a year, sometimes overwintering in southwestern United States, typically unbranched, 2-15 dm. tall, with single lines of stomates and 10-32 ridges; sheaths green and elongate, 7-15 mm long and 3-9 mm bread; teeth 10-32, articulate and typically shedding early with dark rim on sheath remaining.

Leaves

Branches few and irregular to many and whorled, 5- to 6-angled, simple.

None

Spores

Cones pedunculate, blunt, deciduous.

Cone tip rounded; spores green and spheric.

Equisetum palustre

Equisetum laevigatum

Habitat

Streambanks, wet meadows, and marshes, from the lowlands to moderate elevations in the mountains.

Wet places, including meadows and streambanks, at low to middle elevations.

Distribution

Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across the northern U.S. and Canada to the Atlantic Coast; circumboreal.

[WildflowerSearch map]

[BONAP county map]

Occurring chiefly east of the Cascades crest in Washngton; southern British Columbia to California, east to the Rocky Mountains, Great Plains, Great Lakes region, and northeastern North America.

[WildflowerSearch map]

[BONAP county map]

Origin

Native

Conservation status

Not of concern

Sibling taxa