Equisetum variegatum Schleicher ex F. Weber & D.Mohr var. nelsonii A.A. Eaton, Fern Bull. 12: 41. 1904

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.

Equisetum × nelsonii , the hybrid between E . laevigatum and E . variegatum , is often mistaken for small forms of E . × ferrissii .