CHAPTER 1
 LITERATURE REVIEW

 Cycads

 Cycads are an ancient group of plants, sometimes called the coelacanthss of the

plant world," that date back to the Paleozoic era (Moretti 1990). However, the true rise

and dominance of the cycads occurred during the Mesozoic era. Cycads are believed to

be an evolutionary intermediate between ferns and flowering plants (Whiting 1962).

Cycads belong to three families: Cycadaceae which includes a single genus, Cycas;

Stangeriaceae which also contains only 1 genus, Stangeria; and Zamiaceae which

contains 8 genera, Bowenia, Ceratozamia, Dioon, Encephalartos, Lepidozamia,

Macrozamia, Microcycas, and Zamia (Whitelock 2002). There are almost 300 species of

cycads worldwide, most of which are found in tropical and subtropical environments

(Hill 2004). Many of these species are endangered or threatened, with this threat due

more to determined collectors than to deforestation, agriculture, and urban sprawl (Giddy

1990).

 While in some cases cycads are used for food or fertilizer, their chief economic

importance is as ornamental landscape plants (Thieret 1958). These plants can be found

in hundreds of nurseries all over the state of Florida. While older and consequently larger

plants can be quite expensive, smaller 1 gallon pot size C. revoluta can sell for as little as

$10.00 (Home Depot). Aside from its natural beauty and hardiness, Cycas revoluta is a

very popular plant with growers because it can be propagated through cutting lateral

outgrowths or "pups".