rica, northward to Canada, and westward to British Columbia 
(, Seemann ). It occupies similar latitudes in temperate Europe, 
and there is found as far north as Smoland. 
Plate 61. Young fertile frond, and another more fully developing its branches, 
of Equisetum (§ Subvernalia) sylvaticum , Linn .,—natural size. Fig. 1. Section 
of a portion of the stem, showing the lacunes. 2. Section of a branch, which 
has no lacunes,— magnified. 
