Gymnosperms (from the Greek terms gymnos, meaning “naked,” and sperma, meaning “seed”) produce seeds that are totally exposed or borne on the scales of cones. The four phyla of gymnosperms are: Coniferophyta, conifers including pine, spruce, hemlock and fir; Ginkgophyta, consisting of one species, the ginkgo or maidenhair tree; Cycladophyta, the cycads or ornamental plants; and Gnetophyta, a collection of very unusual vines and trees.