Equisetum variegatum Schleich. Cat. Helvet. 27. 1807.
This species, in its typical form, is common on sandy or gravelly
shores on the Keweenaw Peninsula, a tongue of land 60 miles in
length, stretching northeasterly into Lake Superior. It is associated
with H. laevigata and Equisetum limosum. I have seen no
indications that either this or the variety anceps is injured by
frost in this state and they are certainly evergreen.
Keweenaw Peninsula, Mich., Farwell 211, May 30, 1885. This
species may be looked for north of 42°. It prefers the borders
of cold streams and ponds.