Burke: Equisetum palustre vs. Equisetum ×ferrissii

	Equisetum palustre	Equisetum ×ferrissii
	marsh horsetail	Ferriss' 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.	Annual to perennial herb, 20-180 cm; sheath 7-17 mm, 3-12 mm broad, commonly with dark bands; teeth 14-32, deciduous or persistent.
Leaves	Branches few and irregular to many and whorled, 5- to 6-angled, simple.	None
Spores	Cones pedunculate, blunt, deciduous.	Cone tip pointed; spores white and mishappen.

	Equisetum palustre	Equisetum ×ferrissii
Habitat	Streambanks, wet meadows, and marshes, from the lowlands to moderate elevations in the mountains.	Dry to wet, often disturbed areas, including gravelly roadsides.
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 Washington; southern British Columbia to California, east across most of North America to the Atlantic Coast. [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. fluviatile, 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, 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 ×ferrissii

marsh horsetail

Ferriss' 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.

Annual to perennial herb, 20-180 cm; sheath 7-17 mm, 3-12 mm broad, commonly with dark bands; teeth 14-32, deciduous or persistent.

Leaves

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

None

Spores

Cones pedunculate, blunt, deciduous.

Cone tip pointed; spores white and mishappen.

Equisetum palustre

Equisetum ×ferrissii

Habitat

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

Dry to wet, often disturbed areas, including gravelly roadsides.

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 Washington; southern British Columbia to California, east across most of North America to the Atlantic Coast.

[WildflowerSearch map]

[BONAP county map]

Origin

Native

Conservation status

Not of concern

Sibling taxa