Cycas are the largest family of cycad plants. There are 90 species within the genus and they appear naturally on no less then three continents. More species are being added as more cycas are discovered or reclassified. You can recognize this type of cycad by the evenly spaced fronds with a prominent central vein. The fronds can be squat and close to the ground or tall and thin. These are hardy, inexpensive types of plants that commonly are available at landscaping or home hardware stores.
The Dioon genus of the cycad family is usually found close to the ground with very few exceptions. These kinds of cycads typically have long, flat leaves and fronds with serrated edges and sharp, tapered tip. The dry conditions of Mexico are where the wild versions of this cycad reside, but tropical species also exist. The cycad's decorative leaves occasionally come in blue and are an attractive addition to southwestern gardens.
The Zamia is the second largest family of cycads after cycas. This is the most mysterious genus. Most Zamia cycads are native to the dense, isolated tropical forest regions of Central and South America. They also have very specific needs regarding their humid and shady habitat so they are not very popular among gardeners in different climates, but in the appropriate climates they are very commonly cultivated as a landscape plant.
Not all of the world`s cycads are numerous and flourishing. The Chigua cycas are found only in the tropical jungles of Colombia. These cycas are on the endangered list. This tiny genus only includes two types of cycads that have almost been wiped out in the wild. The Chigua's leaves resemble the Zamia as they grow low and wide like ferns and favor roughly the same climactic conditions.