Relictual gymnosperms once much more prominent in the Earth's flora, this group of palm-like gymnosperms arose at the beginning of the Triassic and bear their seed on partially expanded sporophylls. There are ten genera of cycads native to tropics, subtropics and warm temperate regions. Many species are very local endemics and severely endangered. Cycads belong to three families separated chiefly by differences in the type of leaf venation: Cycadaceae, a family with one genus, Cycas, and about 20 palm-like species, has a midvein and no laterals; Stangeriaceae, a family with one genus and one fern-like species, Stangeria eriopus, has a midvein and laterals and Zamiaceae, a family with 8 genera (Bowenia, Ceratozamia, Dioon, Encephalartos, Lepidozamia, Macrozamia, Microcycas, Zamia) and about 80 palm-like species, has a number of parallel or wavy, simple or forked veins running longitudinally. Ceratozamia, Dioon, Microcycas and Zamia are native to the New World; the other 6 genera to the Old World.

Cycas circinalis and C. revoluta are widely cultivated for their ornamental, glossy foliage, which is often cut for decorative greens, wreathes and funeral decorations. The female sporophylls of C. circinalis do not form a cone but are loosely whorled-- the seeds are easily visible (recall, this is a "gymno-sperm" ). The specific epithet refers to the "circinnate vernation". This means that, like ferns, the leaves are rolled up when young. The seeds of C. revoluta are eaten by the natives and from the pith of the trunk of this plant and several species of Zamia, a starchy, edible sago is prepared giving rise to the common name "sago palm". This is now known to be carcinogenic. Sago palms are a host to a blue-green algae on its coralloid roots located around the base of the trunk.