Monographs Details: Hippochaete hyemalis var. californica (Milde) Farw.
Authority: Farwell, Oliver A. 1916. The genus Hippochaete in North America, north of Mexico. Mem. New York Bot. Gard. 6: 461-472.

Equisetum hyemale var. californicum Milde; A. A. Eaton, Fern Bull. 11: 113. 1903, as to the biangulate plants only.

Equisetum hiemale-vax. Doellii Milde; A. A. Eaton, Fern Bull. 11:114. 1903, Not Milde, 1863.

Typical H. hyemalis with caducous teeth has never been collected in America. The Pacific coast plants differ in having the teeth deciduous or more or less persistent. The plants referred by Mr. Eaton to the var. Doellii Milde cannot belong there as that European variety has the centrum only one fourth or one third the diameter of the stem, while the British Columbia plants have a centrum four fifths the diameter of the stem and the teeth are not wholly persistent as described, at least on specimens distributed which show them to be generally deciduous. California to British Columbia.