NON-FLOWERING SEED PLANTS

"Most of the non-flowering seed plants, or gymnosperms, are conifers which include the world's tallest plant, the redwood, which attain heights of up to 117 meters and trunk diameters in excess of 11 meters. They also include the pines, firs, and hemlocks. The seeds of conifers are borne in cones. The cyads are palm-like in appearance and have typically large seeds that are also borne in cones. Cyads are found mainly in tropical and subtropical regions and may reach heights of 18 meters or more. The Ginko, a tree of up to 30 meters, is the sole living survivor of a group that has remained unchanged for 80 million years. One of the most dramatic innovations to arise during the evolution of plants was the seed. The survival value of the seed is probably responsible for the dominance of seedplants in today's flora. Seeds contain stored food, and can survive the ravages of time and many environments."