Dwarf Scouring Rush

Equisetum scirpoides

Equisetum scirpoides (dwarf scouring rush or dwarf horsetail) is the smallest of the currently occurring representatives of the genus Equisetum (horsetail).

Sterile stems are multiple from the base, evergreen, have no branches, and bend/coil/twist into a contorted tangle. The “leaves” are reduced to a sheath that surrounds the stem, with 3 black/brown teeth around the top that have distinct white edges and persist all season. There is a black band just above the base of the sheath.

Fertile stems are like the sterile stems but distinguished by the cone, less than 6.3 mm long, at the tip of the stem. Cones have a sharp-pointed tip, mature in late summer or may over-winter and release spores the following spring.
Equisetum scirpoides Equisetum scirpoides plant growing in a moist seepy area along a river under White Cedar (Thuja occidentalis) trees. Dwarf Scouring Rush,Equisetum scirpoides,Geotagged,Minnesota,Spring,Thuja occidentalis,United States,white cedar

Appearance

Aerial stems persisting more than a year, unbranched, tortuous, 2.5--28 cm; lines of stomates single; ridges 6. Sheaths green proximally, black distally, elliptic in face view, 1--2.5 × 0.75--1.5 mm; teeth 3, dark with white margins, not articulate to sheath. Cone apex pointed; spores green, spheric. 2 n =216.

Naming

Equisetum scirpoides Michaux, Fl. Bor.-Amer. 2: 281. 1803.

Distribution

Austria, Finland, Norway, Spitsbergen, Sweden, Greenland, St. Pierre & MiqueIon, Canada (Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland, N.W.Territories, Nunavut, Nova Scotia, Ontario, Prince Edward Isl., Quebec, Saskatchewan, Yukon), Alaska, USA (Idaho, Illinois, Iowa, Maine, Massachusetts, Michigan, Minnesota, Montana, New Hampshire, New York, South Dakota, Vermont, Washington, Wisconsin), W-Siberia, C-Siberia, E-Siberia, Amur, Ussuri, Japan, Lithuania, Novaja Zemlja, Kamchatka, N-European Russia, Lithuania, Estonia, C-European Russia, E-European Russia.

Habitat

Wet woods, mossy wetlands, peat bogs, tundra.

Reproduction

By spores and rhizomes. Spore cones have a sharp-pointed tip, mature in late summer or may over-winter and release spores the following spring.

References:

Some text fragments are auto parsed from Wikipedia.

http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500625
https://www.minnesotawildflowers.info/fern/dwarf-scouring-rush
https://en.wikipedia.org/wiki/Equisetum_scirpoides
Taxonomy
KingdomPlantae
DivisionPolypodiophyta
ClassEquisetopsida
OrderEquisetales
FamilyEquisetaceae
GenusEquisetum
SpeciesEquisetum scirpoides
Photographed in
United States of America