Cycads are actually a unique assemblage of plants and although they are grouped with the gymnosperms they are in fact unrelated to any other group of living plants. Cycas species are by far the most widely distributed genus, with representatives occurring as far north as Japan and China, and others being scattered through Asia, various islands of the Pacific, Australia and the east coast of Africa and Madagascar. Cycads produce naked seeds and are thus included in the phylum of the plant kingdom known as the Spermatophytes, as their seeds are produced on exposed leaf-like structures (termed sporophylls) and male pollen emerges from a cone, not enclosed within an ovary as in the flowering plants. They have been on our planet since before mankind and are sometimes known as dinosaur plants because of their ancient ancestry.