plant

plant Multicellular organism whose cells have cellulose cell walls and contain chloroplasts or similar structures (plastids). They develop from diploid embryos, and have a regular alternation of haploid and diploid generations in their life cycle. Most plants are green and make their own food by photosynthesis. A few are colourless parasites or saprophytes. Simple plants reproduce by means of spores, while more advanced plants produce seeds and fruits. Plants show a wide range of biochemistry; some produce chemicals such as alkaloids, narcotics, and even cyanide; others secrete substances into the soil to prevent other plants growing near them. Many of these chemicals form the bases for the development of drugs. Plants are classified on the basis of their morphology (shape and structure). The most important phyla are: the Bryophyta (bryophytes), which include the mosses and liverworts; Lycopodophyta, or club mosses; Sphenophyta (horsetails); Filicinophyta (ferns); Cycadophyta (cycads); Ginkgophyta (ginkgo); Coniferophyta (conifers); and Angiospermophyta (angiosperms). See also alternation of generations