Plant

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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 sequoia trees, the largest living organisms, which can draw water and minerals through their vascular systems to elevations of more than 100 m (330 ft).

Only a tiny percentage of plant species are directly used by humans for food, shelter, fiber, and drugs. At the head of the list are rice, wheat, corn, legumes, cotton, conifers, and tobacco, on which whole economies and nations depend. Of even greater importance to humans are the indirect benefits reaped from the entire plant kingdom and its more than 1 billion years of carrying out photosynthesis. Plants have laid down the fossil fuels that provide power for industrial society, and throughout their long history plants have supplied sufficient oxygen to the atmosphere to support the evolution of higher animals. Today the world's biomass is composed overwhelmingly of plants, which not only underpin almost all food webs, but also modify climates and create and hold down soil, making what would otherwise be stony, sandy masses habitable for life.

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