The non-seed plants include the bryophytes and the pteridophytes. The bryophytes (mosses and liverworts) generally require a moist (damp) shady environment for active growth and reproduction, although some tolerate dry areas. The pteridophytes (ferns) range from the tropics to the arctic circle with most species living in the tropical rain forest where they perch high in the branches of trees. In temperate regions, ferns commonly inhabit swamps, marshes, moist woodlands, and stream banks, although some species can be found in fields, rocky crevices on cliffs or mountains, or even deserts.