Burke: Equisetum palustre vs. Equisetum fluviatile

	Equisetum palustre	Equisetum fluviatile
	marsh horsetail	river horsetail, swamp horsetail, water horsetail
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 annual, the stems not dimorphic, up to 1 m. tall, shallowly 9- to 25-ridged and grooved, the ridges smooth; stomata in a single broad band in each furrow; central cavity large, more than 3/4 the diameter of the stem; sheaths green, 4-9 mm. long, with persistent, sharp, black teeth 1.5-3 mm. long.
Leaves	Branches few and irregular to many and whorled, 5- to 6-angled, simple.	Branches none to many and whorled, 4- to 6-angled, simple, the first internode shorter than the stem sheath.
Spores	Cones pedunculate, blunt, deciduous.	Cone short-pedunculate, blunt, deciduous.

	Equisetum palustre	Equisetum fluviatile
Habitat	Streambanks, wet meadows, and marshes, from the lowlands to moderate elevations in the mountains.	Shallow water, marshes and bogs, along muddy shores, from the lowlands to moderate elevations in the mountains.
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 on both sides of the Cascades crest in Washington; Alaska to Oregon, east to the northern Rocky Mountains and northern 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. hyemale, E. laevigatum, 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, 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

Equisetum fluviatile

marsh horsetail

river horsetail, swamp horsetail, water horsetail

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 annual, the stems not dimorphic, up to 1 m. tall, shallowly 9- to 25-ridged and grooved, the ridges smooth; stomata in a single broad band in each furrow; central cavity large, more than 3/4 the diameter of the stem; sheaths green, 4-9 mm. long, with persistent, sharp, black teeth 1.5-3 mm. long.

Leaves

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

Branches none to many and whorled, 4- to 6-angled, simple, the first internode shorter than the stem sheath.

Spores

Cones pedunculate, blunt, deciduous.

Cone short-pedunculate, blunt, deciduous.

Equisetum palustre

Equisetum fluviatile

Habitat

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

Shallow water, marshes and bogs, along muddy shores, from the lowlands to moderate elevations in the mountains.

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 on both sides of the Cascades crest in Washington; Alaska to Oregon, east to the northern Rocky Mountains and northern Great Plains, Great Lakes region, and northeastern North America.

[WildflowerSearch map]

[BONAP county map]

Origin

Native

Conservation status

Not of concern

Sibling taxa