Conifers are the dominant plants in colder forests of the temperate regions, and are thus prominent in larger regions of the world. They are very important ecologically and provide many economically important products, such as lumber and paper. The largest of all organisms, the giant sequoias belong to this group. Division Cycadophyta - cycads Cycads have pinnately compound leaves and resemble large ferns or small palms. This is a small group comprising about 10 genera of tropical plants.
Cycads are dioecious, having separate male and female plants.
Their life cycle is essentially like that of pine and other conifers. The leaves are broad, with dichotomous venation. Like cycads, Ginkgo is dioecious, having separate male and female plants, The life cycle essentially like that of cycads. We discuss only Welwitschia mirabilis, a very odd plant native to coastal African deserts. The flowering plants are the largest plant group, with over 200,000 species.