Plants Plant, any member of the plant kingdom, comprising about 260,000 known species of mosses, liverworts, ferns, herbaceous and woody plants, bushes, vines, trees, and various other forms that mantle the earth and are also found in its waters. Plants range in size and complexity from small, nonvascular mosses, which depend on direct contact with surface water, to giant redwood trees, the largest living organisms, which can draw water and minerals through their vascular systems to elevations of more than 100 m (more than 330 ft). Only a tiny percentage of plant species are directly used by humans for food, shelter, fiber, and drugs. At the head