Is covered with a wrinkled bark, as in Cycas siamensis, which has a stem of unusual form (fig.
In Cycas revoluta and C. circinalis each leaf-like carpel may produce several laterally attached ovules, but in C. Normanbyana the carpel is shorter and the ovules are reduced to two; this latter type brings us nearer to the carpels of Dioon, in which the flower has the form of a cone, and the distal end of the carpels is longer and more leaf-like than in the other genera of the Zamieae, which are characterized by shorter carpels with thick peltate heads bearing two ovules on the morphologically lower surface.
The climbing species of Gnetum are characterized by the production of several concentric cylinders of secondary wood and bast, the additional cambium-rings being products of the pericycle, as in Cycas and Macrozamia.
In Cycas the stem apex, after producing a cluster of carpellary leaves, continues to elongate and produces more budscales, which are afterwards pushed aside as a fresh crown of fronds is developed.
In the tropical zone large figs abound, Terminalia, Shorea (sal), laurels, many Leguminosae, Bombax, Artocarpus, bamboos and several palms, among which species of Calamus are remarkable, climbing over the largest trees; and this is the western limit of Cycas and Myristica (nutmeg).
In Cycas whorls of scales alternate with large pinnate leaves.
As a fairly typical and well-known example of the Cycadaceae, a species of the genus Cycas (e.g.
The male flower of Cycas conforms to the type of structure characteristic of the cycads, and consists of a long cone of numerous sporophylls bearing many oval pollen-sacs on their lower faces.
In some species of Cycas the leaf-bases do not persist as a permanent covering to the stem, but the surface F F FIG.
In Cycas the carpels are ordinary leaves, with ovules upon their margin.