Division Pterophyta
The Pterophyta includes the ferns. Ferns represent the second major step in the evolutionary sophistication of plants. The division Pterophyta is a group of non-seed plants with a fossil record dating back to the lower Devonian. The division consists of about 11,000 living species. While they still reproduce by spores, like mosses, the ferns add a vascular system -- i.e. specialized organs for trasporting fluids throughout the plant. These plants are vascular but do not have seeds or pollen. Ferns prefer to live in environments having low light and relatively high levels of moisture and humidity. For this reason they flourish in tropical forests.