Cycads

Classification
Cycads are descendents of a very ancient group of early seed-bearing plants. Cycads appeared on the earth during the Pennsylvanian period, from 310 to 285 million years ago. Presently, there are three families of cycads (Cycadaceae, Stangeriaceae and Zamiaceae) containing 11 genera and approximately 185 species. However, 150 million years ago during the Jurassic period, cycads were at their prime and covered vast areas of the earth's surface. During this period, cycads coexisted with dinosaurs and other animals, such as amphibians. While most species of dinosaurs were extinct by 65 million years ago, cycads continue to survive on this earth.
 
Habitat & Range
Cycads grow scattered in habitats such as the understories of tropical rain forests and seasonally dry forests, loose stands in grasslands, and at high elevations in eastern Africa. Cycads presently grow in tropical and subtropical regions of North America, South America, Africa, Asia and Australia. Although they are widespread worldwide, cycads generally grow in small, localized populations. 		Physical Characteristics
Cycads have single stems with a crown of large pinnate (similar to a feather with leaflets extending from each side of the axis) leaves and appear somewhat similar to palms, though they are not closely related. Most cycads are rather large, some species reaching up to 60 feet (18 m) or more in height. Cycads carry male reproductive structures (pollen grains) and female reproductive structures (seeds) on different plants. Both pollen and seeds are borne in cones, similar to the cone-bearing trees of the Pacific Northwest. Cycad seeds are large with a brightly colored outer coat and a hard stony inside layer. Animals, attracted by the colors of the seeds, will often eat the outer coat, leaving the inner part to germinate).

Fascinating Facts

  • Only one species of cycad, Zamia pumila, has a range that extends into the United States. The distribution of this Caribbean species includes southeastern parts of Georgia and southern parts of Florida where it is currently endangered.
  • Seminole Indians of the southeastern United States made use of the starchy matter in the stems of the cycad Zamia pumila as an ingredient in bread. Most cycads contain toxic compounds within their tissues. Like other cycads eaten as food, the starch was ground and leached in order to decrease the toxicity prior to consumption.
  • The roots of cycads host symbiotic bacteria that fix nitrogen from the air into a form usable by plants
  • Cycads were long thought to be pollinated by the wind. It has been shown, however, that beetles, particularly weevils, and small bees are important pollinators of these plants. Some cycads produce heat or odors to attract these insects.
  • Although the leaves of cycads resemble those of palms the two groups are not closely related. Cycads have naked seeds borne in cones. Palms are flowering plants whose seeds develop in fleshy fruits. Ån example of the popular confusion of these two groups is the use of the common name “"sago palm" for both a cycad species (Cycas revoluta) and a palm species (Metroxylon sagu).

Cycads are becoming increasingly endangered. Currently, approximately 80 species of cycads are listed under Appendix I to CITES and are thus considered to be endangered. These represent roughly 44 percent of all known cycad species. Cycads are vulnerable for a number of reasons. These plants tend to grow in habitats such as tropical forests that are significantly altered by habitat destruction. Cycads grow slowly and reproduce infrequently. In addition, cycads have been extensively collected from the wild. Because of their close relationships with their insect pollinators, the decline of cycad species may also influence the populations of these insects. Some of these insect pollinators are as ancient as cycads themselves, thus, the close relationships between these organisms have developed over millions of years.

Several institutions are now involved in breeding and conservation programs for threatened cycad species. If you are a fan of cycads and wish to include them in your garden, be sure that the seeds or plants you buy were not collected from the wild. Educate yourself and others about these fascinating plants and promote their conservation. Woodland Park Zoo exhibits cycads in its bioclimatic zones, including Tropical Rain Forest and Tropical Asia. Through its naturalistic bioclimatic zones and educational materials and programs Woodland Park Zoo fosters an understanding and appreciation of endangered plants, animals and their habitats.

How You Can Help!
Contact Woodland Park Zoo at 206.548.2500 to find out ways you can support conservation programs at the zoo. Learn other ways you can help conserve wildlife and the habitats they require for survival by visting our How You Can Help webpage..