1. A key based on topographical characters of leaflets is workable for genera. 2. The leaflets of the different species vary in color from bright green to dark green or dull gray-green; the shape and texture of the leaflets show an equal amount of variation. 3. A thick-walled, cutinized epidermis is characteristic of all the species examined; and a hypodermis is differentiated to some extent in all the species studied except Bowenia. 4. A well differentiated upper palisade is present in Cycas, Dioon, Encephalartos, Ceratozamia, Macrozamia, and Zamia furfuracea. Other species of Zamia show a more or less palisade region, but the cells are scarcely elongated or regular enough to constitute a true palisade. 5. The spongy mesophyll in most of the species examined is composed of transversely elongated cells. In nine of the species the cells are yoke-shaped. 6. In all of the species studied, thick-walled cells are found around the vascular bundles or scattered through the mesophyll. 7. Mucilage canals are prese...