Cycad plants are most often characterized by their stout, woody trunk topped with a crown of large, hard and stiff evergreen leaves. The individual plants are either all male or all female. Cycads size varies between types, some having trunks only a few centimeters to others several meters tall. They grow very slowly and live very long, with some specimens known to be as much as 1,000 years old. Because of their superficial resemblance, they are sometimes confused with and mistaken for palms or ferns, but are only distantly related to either.
Considered by many to be the world’s oldest living plants, cycads have been arounds since the Jurrassic age, over 250 million years ago. Though they are a minor component of the plant kingdom today, during the Jurassic period they were extremely common. However, little has changed with these plants since the Jurassic, compared to some major evolutionary changes in other plant divisions. Cycads are found across much of the subtropical and tropical parts of the world. Some can survive in harsh semidesert climates, others in wet rain forest conditions, and some in both. Some can grow in sand or even on rock, some in oxygen-poor, swampy, bog-like soils rich in organic material, and some in both. Some are able to grow in full sun, some in full shade while others are adaptable to both. A few are even salt tolerant.
All told, there are an estimated 305 different cycad species falling under three family names; Cycadaceae, Stangeriaceae and Zamiaceae. Under Cycadaceae you have all the plants in the Cycas subfamily. Under Stangeriaceae you have those in the Stangeria and Bowenia sub family. And under Zamiaceae you have the largest variety of cycads, which include Dioon, Encephalartos, Macrozamia, Lepidozamia, Ceratozamia, Microcycas, Chigua and Zamia.
In recent years, many cycads have been dwindling in numbers and may face risk of extinction because of theft and unscrupulous collection from their natural habitats, as well as from habitat destruction. Many are severely endangered in their natural habitat, while some are very common and at no threat of extinction. Some however have lost their habitat and are no longer found in the wild. Because of this, ALL cycads are in the CITES appendix appearing under the heading Plant Kingdom and under their repsective family names.