Living fossils of the plant world, the cycads can trace their lineage back to about 300 million years ago. In a world without flowers, forests of these palm-like plants were the main feature of the dinosaurs' landscape. Today the cycads (http://www.nybg.org/events/prel_landsc.html) are mere vestiges of their glorious past: an estimated 19 genera are known only as fossils and of the 11 living genera, most are on the verge of extinction because of loss of habitat, slow growth, and infrequent reproduction. In a joint project with Fairchild Tropical Garden, Dr. Dennis Wm. Stevenson, Director of the Harding & Lieberman Laboratories at The New York Botanical Garden and the world's leading expert on cycads, is studying their pollination biology. His work confirmed that cycads are pollinated by specific species of weevils (http://www.nybg.org/events/prel_weevil.html)and beetles and unravelled the symbiosis -- mutually beneficial relationship of two dissimilar organisms living together -- between plants and pollinators, demonstrating that the cycads' survival is contingent upon the preservation of their ecosystem. Pollination -- the transfer of the sperm-cell-loaded pollen from the male structure to the female structure for germination -- involves separate male and female cycad plants with reproductive structures called cones produced when both plants reach maturity. The pollen-laden male cone differs in shape, size, and color from the female cone. Dr. Stevenson's study of Zamia furfuracea (http://www.nybg.org/events/prel_2.html,) Zamia pumila, and Dioon califanoi showed that each cycad genus has its own genus of pollinators and each cycad species has its own species of pollinators. He uncovered a fascinating tale of plant/animal interdepedence where each participant follows a precise sequence of events and plays a specific role in order to ensure the propagation of both species. In this quid pro quo relationship, the insects perform the pollination and the cycads in turn offer the insects food, shelter, a breeding site, and larvae protection.
The above story is based on materials provided by New York Botanical Garden. Note: Materials may be edited for content and length.
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