There are about 375,000 species of plants, with more being discovered each year. This includes seed plants, bryophytes, ferns and relatives of ferns called fern allies. Some 297,326 species of plants have been identified, of which 258,650 are flowering and 15,000 bryophytes (liverworts, hornworts, and mosses). All plants are photosynthetic, utilizing carbon dioxide, water and light energy to produce oxygen and sugars.