is no ovary, the ovule being exposed to view resting on the edge of the leaf (Fig. 135, a); the ovule is fertilized by the falling of the pollen, style and stigma being absent as well as ovary. Plants of this kind are called, therefore, Gymnospermae, or naked seeds; whereas those having an ovary are known as Angiospermae, or seed-vessels. The flowering plants divide naturally, therefore, into these two groups. To the Gymnospermae, or plants with naked seeds, belong the Bread-tree, Zamia, and Cycas (Cycadae), the Pine, Fir, Cypress, Juniper, Cedar, and Yew (Coniferae). Among the Angiospermae, or plants whose seeds are contained in seed-vessels, are found the forest-trees, fruit-trees, grasses, roses, violets, etc.
CYCADAE.
The Cycadae are small palm-like trees (Fig. 137), or shrubs with unbranched stems, found principally in the tropical regions of Asia and America. The Bread-tree belongs to this order, supplying the Caffre bread; the Cycas of Japan produces, in its stem, a starchy matter, which is collected and eaten like sago. The Cycadae are sometimes called Palm-ferns, from their resembling Ferns as well as Palms. In past time the order was much more numerous than at present. The so-called flower of the Cycadae is very simple. The naked ovules are attached to the bases of contracted leaves: these leaves in some cases overlap each other. The stamens are found on separate leaves, which overlap each other, forming a cone. The leaves containing the ovules and stamens are found on separate plants, the series being quite distinct in the Cycadae. The reproductive apparatus of the Cycadae agrees essentially with that of the Salvinia, noticed in speaking of the Rhizocarpae, the ovule of the Cycas being homologous with the large spore of Salvinia, the pollen corresponding to the small spores. As the reproduction of the Cycas
