One of the two divisions of the seed plants of about 600 to 700 species extant on all continents except Antarctica. The most familiar and common representatives are the evergreen, cone-bearing trees of the Pinales. Because the ovules (young seeds) are exposed directly to the air at the time of pollination, the Pinophyta are commonly known as the gymnosperms, in contrast to the other division of flowering plants, the angiosperms (division Magnoliophyta), which have the ovules enclosed in an ovary. The division Pinophyta consists of three classes: Ginkgoopsida, Cycadopsida, and Pinopsida.