cycad

views updated May 29 2018

cycad Phylum (Cycadophyta) of primitive palm-like shrubs and trees that grow in tropical and subtropical regions. Although they are gymnosperms, they have feathery palm- or fern-like leaves (poisonous in most species) at the top of stout (usually unbranched) stems. In addition to their main roots, they also have special roots containing cyanobacteria that carry out nitrogen fixation. These plants first flourished c.225 million years ago. Most of the 100 or so surviving species are less than 6m (20ft) tall.

cycad

views updated Jun 11 2018

cy·cad / ˈsīkəd; ˈsīˌkad/ • n. a palmlike plant (genus Cycas and other genera, family Cycadaceae) of tropical and subtropical regions, bearing large male or female cones.

cycad

views updated May 08 2018

cycad See CYCADOPSIDA.

cycad

views updated Jun 08 2018

cycad See CYCADOPHYTA.