Cycadophyta

Cycadophyta is a division of gymnosperms comprising the living cycads, a small and ancient lineage of seed-producing plants. They are often superficially palm-like but are only distantly related to true palms. Modern cycads occur mainly in tropical and subtropical regions and form a relictual group with a rich fossil history dating back to the Paleozoic era.

Cycads are typically shrubs or small trees with stout trunks and a crown of large, evergreen, pinnate leaves. The leaves are often rigid and hard, with leaflets arranged along a central rachis. A distinctive feature is the coralloid root system that hosts symbiotic cyanobacteria, such as Nostoc, which fix atmospheric nitrogen for the plant. Cycads are dioecious, with separate male and female individuals. They reproduce by producing strobili or cones rather than true flowers; male cones release pollen, and female cones develop seeds that are sometimes covered by a fleshy aril. In many species, pollination is facilitated by beetles rather than by wind.

Taxonomically, living cycads are divided into two families, Cycadaceae and Zamiaceae, containing genera such as Cycas, Zamia, Dioon, Encephalartos, and Macrozamia. They have a long fossil history and were among the dominant gymnosperms in the Mesozoic era. Today, the majority of species are restricted to limited geographic ranges and many face threats from habitat loss and over-collection.

Conservation and cultivation are central to cycads today; numerous species are listed under conservation frameworks and CITES regulations to curb illegal trade. In cultivation, they are prized as ornamental plants and for their distinctive morphology and ancient lineage.