Amer. Fern J. 16: 46. 1926.
Aerial stems persisting less than a year or only the proximal part overwintering, unbranched, 20–60 cm; lines of stomates single; ridges 6–14. Sheaths green, elongate, 3.5–7.5 × 2–4 mm; teeth 6–14, centers brown and margins white, prominent, tip usually brown, long, filiform. Cone apex pointed; spores white, misshapen.
Phenology: Cones maturing in early summer, but spores not shed.
Habitat: Lakeshores, riverbanks.
Ont., Que., Ill., Ind., Mich., Minn., Mont., N.Y., Oreg., Wis., Wyo.
Equisetum × nelsonii, the hybrid between E. laevigatum and E. variegatum, is often mistaken for small forms of E. × ferrissii.