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Cycads in South Africa. Cycads / ˈ s aɪ k æ d z / are seed plants that typically have a stout and woody trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male or female. Cycads vary in size from having trunks only a few centimeters ...
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Cycads all over the world are in decline, with four species on the brink of extinction and seven species have fewer than 100 plants left in the wild. [2] 23,420 species of vascular plant have been recorded in South Africa, making it the sixth most species-rich country in the world and the most species-rich country on the African continent.
While there are more than 200 species of cycads, only one is native to Florida, and only a couple are popular landscaping plants in our area.
Cycas is a genus of cycad, and the only genus in the family Cycadaceae with all other genera of cycad being divided between the Stangeriaceae and Zamiaceae families. Cycas circinalis, a species endemic to India, was the first cycad species to be described in western literature, and is the type species of the genus.
The leaf-like character of Sporophylle gives Dioon a special position within the cycads. Dehgan & Dehgan described the genus as the most primitive of the cycads and suggested they put them into their own family. [15] A molecular genetic study of the chloroplast DNA revealed that it is at least the most primitive genus of neotropical cycads. [16]
Dioon edule, the chestnut dioon, is a cycad native to Mexico, also known as palma de la virgen. Cycads are among the oldest seed plants and even pre-date the dinosaurs. [3] It belongs to the Zamiaceae plant family within the order Cycadales.
The sperm of members from the genus are large, as is typical of cycads, and Z. roezlii is an example; its sperm are approximately 0.4 mm long and can be seen by the unaided eye. [11] It was long believed that Zamia plants, like all cycads, relied completely on wind pollination.