Cycad

Cycadales
Temporal range:
Cycas rumphii with old and new male strobili
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Spermatophytes
Clade: Gymnospermae
Division:
Bessey 1907: 321.[2]
Class:
Brongn.[1]
Order:
Pers. ex Bercht. & J. Presl
Extant groupings
  • Cycadaceae
  • Zamiaceae
Synonyms
  • Cycadofilicales Němejc 1950
  • Dioales Doweld 2001
  • Stangeriales Doweld 2001
  • Zamiales Burnett 1835

Cycads /ˈskædz/ are seed plants with a stout, woody cylindrical trunk with a crown of large, hard, stiff, evergreen and usually pinnate leaves. The species are dioecious, that is, individual plants of a species are either male or female. Cycads vary in size from having trunks only a few centimeters to several meters tall. They typically grow slowly and have long lifespans. They superficially resemble palms or ferns, but are not closely related to either group. Cycads are gymnosperms. Cycads have specialized pollinators, usually a specific beetle, and more rarely a thrips or a moth.

Both male and female cycads bear cones (strobili), somewhat resembling conifer cones. Cycads fix nitrogen in association with cyanobacteria living in the plants' roots. Some species are used as narcotics, while in Vanuatu the plant symbolizes peace and appears on the national flag. Cycads all over the world are in decline, with four species on the brink of extinction and seven species having fewer than 100 plants left in the wild.

  1. ^ Brongniart, A. (1843). Énumération des genres de plantes cultivées au Muséum d'histoire naturelle de Paris.
  2. ^ Bessey, C.E. (1907). "A synopsis of plant phyla". Nebraska University Studies. 7: 275–373.