How many types of plants are there?

There are thought to be between 250,000 and 315,000 species of plants in the kingdom Plantae. The kingdom encompasses ferns, conifers, trees, mosses, flowering plants with seeds, green algae and all other plants that derive energy through carbon from photosynthesis.

The hundreds of thousands of species of plants are classified into four major groups: green algae; bryophytes, which include worts and mosses; pteridophytes, which include ferns and club mosses; and seeded plants, which include conifers and flowering plants. Fungi and red and brown algae are not included in the kingdom of Plantae because they do not fuel themselves with photosynthesis.