in their adopted habitats. Such, then, is a general suggestion of the position this plant group holds in our American flora. Let us now outline the relations of its three members to each other and to other flowering plants in general.
It is worthy of note that the three types referred to bear no close relationship to one another; on the contrary, they stand in distinct and rather parallel classes, and each respectively among the most perfect developments of its class. The cacti, on the one
Fig. 4.—Agave Salmiana in Blossom, and Agave Americana in Foreground.
hand, hold a place among the most highly organized of dicotyledons; while the agaves and yuccas belong in the other great class of angiospermous flowering plants, nearly parallel, but lower ranked—the monocotyledons. Further, the agaves and yuccas stand in nearly parallel divisions among monocotyledons—the agaves among the epigynous-flowered monocotyls, typified by the amaryllis family; the yuccas among the hypogynous-flowered
