Cluster of leaves at the top of a <em>Dioon</em> stem.
Ryan McMillen Southern Illinois University Plant Biology 1125 Lincoln Drive Carbondale Illinois 62901 USA Dumbremindr@aol.com
Dioon, Leaves, Cycad
Dioon spinulosum is a gymnosperm that links ancient plants to today. With an explosion in the Mesozoic era, in concert with dinosaur diversification, this era is often referred to as the "Age of Cycads and Dinosaurs". The leaves of cycads occur in a cluster at the top of the stem and resemble palms. Unlike palms, cycads exhibit true secondary growth from a vascular cambium.