Equisetum laevigatum

Aerial stems lasting less than a year, occasionally overwintering in the southwestern United States, usually unbranched, 20–150 cm; lines of stomates single; ridges 10–32. Sheaths green, elongate, 7–15 × 3–9 mm; teeth 10–32, articulate and usually shed early, leaving dark rim on sheath. Cone apex rounded to apiculate with blunt tip; spores green, spheric. 2n =216.

Phenology: Cones maturing in spring–early summer.
Habitat: Moist prairies, riverbanks, roadsides
Elevation: 1530–3500 m

Alta., B.C., Man., Ont., Que., Sask., Ariz., Ark., Calif., Colo., Idaho, Ill., Ind., Iowa, Kans., Mich., Minn., Mo., Mont., Nebr., Nev., N.Mex., N.Dak., Ohio, Okla., Oreg., S.Dak., Tex., Utah, Wash., Wis., Wyo., n Mexico including Baja California.

Discussion

Schaffner named this species Equisetum kansanum because he applied the name E. laevigatum to what we now know is the hybrid E. × ferrissii. The coarser-stemmed, occasionally persistent forms in the southwestern United States have been called Equisetum funstonii.

Selected References

None.

Lower Taxa