cycad (redirected from Cycadales)

cycad (sī`kăd), any plant of the order Cycadales, tropical and subtropical palmlike evergreens. The cycads, ginkgoes, and conifers comprise the three major orders of gymnosperms, or cone-bearing plants (see cone and plant). The cycads first appeared in the Permian period. They are the most primitive of the living seed-bearing plants and in many ways resemble the ferns. Some have tuberous underground stems, with the crown of leathery, glossy, fernlike leaves springing from ground level; others have a columnar stem, usually 6 to 10 ft (1.8–3.1 m) high (though the corcho of Cuba reaches 30 ft/9.1 m), and are often mistaken for palms. There are 11 genera composed of less than 150 species, some found in very restricted areas. Many cycads (e.g., the fern palm of the Old World tropics and the nut palm of Australia) bear poisonous nutlike seeds. The pith of the coontie (Zamia floridana) yields a starch called Florida arrowroot or sago; the coontie is often called sago palm. Cycads are grown as ornamentals in warm regions and in greenhouses. The cycads are classified in the division Pinophyta, class Cycadopsida.

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cycad

Any of the palmlike woody plants that constitute the order Cycadales, containing four families: Cycadaceae, Zamiaceae, Stangeriaceae, and Boweniaceae. Cycads have crowns of large, feathery compound leaves and cones at the ends of their branches. Some have tall, unbranched, armourlike trunks; others have partially buried stems with swollen trunks. Slow-growing cycads are used as ornamental conservatory plants, but some survive outdoors in temperate regions. The stems of some cycads yield starch that is edible if thoroughly cooked. The young leaves and seeds of others also are edible.