Key to the Genera
This key, in illustrating each genus, follows the method of Clute in “Our Ferns in Their Haunts,” but substitutes other and larger specimens. Five of these are from Waters’ “Ferns” by permission of Henry Holt & Co.
As the indusium, which often determines the name of a fern, is apt in some species to wither early, it is important to secure for study not only a fertile frond, but one in as good condition as possible. For convenience the ferns may be considered in two classes.