Reproduction in which new individuals are produced from a single parent without the formation of gametes. It occurs chiefly in lower animals, microorganisms, and plants. In microorganisms and lower animals the chief methods are fission (e.g. in protists), fragmentation (e.g. in some aquatic annelid worms), and budding (e.g. in cnidarians and yeasts). The principal methods of asexual reproduction in plants are by vegetative propagation (e.g. bulbs, corms, tubers) and by the formation of spores. Spore formation occurs in mosses, ferns, and other plants showing alternation of generations, as a dormant stage between sporophyte and gametophyte, and in some algae and fungi, to produce replicas of the organism. Compare sexual reproduction.