Monographs Details: Hippochaete prealta var. affinis Farw.
Authority: Farwell, Oliver A. 1916. The genus Hippochaete in North America, north of Mexico. Mem. New York Bot. Gard. 6: 461-472.
Description:Distribution and Ecology - Keweenaw Peninsula, Mich.,Farwell 209, May 30, 1885. Palmer Park, Mich., Farwell 209a, July 15, 1902. Rochester, Mich., Farwell 3694 and 3695, June 28, 1914; 3925, 3926, October 25, 1914; 3929 1/2, October 29, 1914. Parkedale Farm, Mich., Farwell 3922 1/2 October 25, 1914; 3984 1/2, June 20, 1915. From the Atlantic to the Pacific but most common east of the Mississippi River.
Equisetum robustum var. affine Engelm. in A. Br. Am. Jour. Sci. 46: 88. 1843.
Equisetum hiemale var. pumilum A. A. Eaton, Fern. Bull. 11: 109. 1903.
Equisetum hiemale var. affine (Engelm.) A. A. Eaton, Fern. Bull. 11: III. 1903.
Differs from the species in its longer sheaths which are 1/3-2 times as long as broad, and in the teeth, which are caducous. Where this variety and the species overlap they intergrade and pass insensibly one into the other, indicating that there is but one species, although the extremes seem distinct enough.
Distribution:United States of America North America