(WITH SIX FIGURES) Genera in the cycads are not only so distinct that they are easily recognizable, but they are so sharply defined that interrelationships within the family are uncertain. Sister MARY ALICE' constructed a key to the genera, based upon the leaflets. A similar key, impractical to apply, but nevertheless effective wherever material is available, could be-based upon pollen tube structures. The usual keys, based upon cones, are very effective when cones are available. Some species are almost as sharply limited as the genera; but others, especially in the larger genera, present such variation that identification is difficult, and it is likely that new species have been described when no new description was needed. In Macrozamia there is a plexus of forms, with M. spiralis as a center, which might afford a better study in variation than in taxonomy, for the description of species might degenerate into a description of individuals. There are similar centers in all the larger genera, especially in Zamia, which contains more than a third of all the species in the family. Consequently, one should exercise some caution in describing new species in cycads. Nevertheless, there are doubtless many new species of this family still waiting to be discovered and described. Two species of Zamia, from Mexico, are sufficiently distinct to be described as new. One I raised from a seed secured near Jalapa, and the other I dug up near Tuxtepec. The former has been under observation in my collection for nearly twenty years, and the latter for fifteen years. Before venturing to describe these plants as new species, I examined all the Zamia material at Kew, both in the herbarium and in the greenhouses. I also had the pleasure of studying the collection in the greenhouse and herbarium of the New York Botanical Garden, doubtless the most extensive collection of Zamia in the world. Dr.