7. Equisetum pratense Ehrhart, Hannover. Mag. 22: 138. 1784.
Meadow horsetail, prêle des prés
Aerial stems dimorphic; vegetative stems green, branched, 16--50 cm; hollow center 1/6--1/3 stem diam. Sheaths somewhat elongate, 3--5 × 2--4 mm; teeth 8--18, narrow, 1.5--4 mm, centers dark and margins white. Branches in regular whorls, horizontal to drooping, solid; ridges 3; valleys channeled; 1st internode of each branch equal to or longer than subtending stem sheath; sheath teeth deltate. Fertile stems brown, with stomates, initially unbranched, persisting and becoming branched and green after spore discharge.
Cones maturing in late spring. Meadows, wet woodlands; 0--2000 m; Alta., B.C., Man., N.B., Nfld., N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon; Alaska, Conn., Ill., Iowa, Maine, Mass., Mich., Minn., N.H., N.Y., N.Dak., Vt., Wis.; n Eurasia to ne China, Japan in Hokkaido.