People are often astonished at how many plants there are in the world. Estimates of course vary, but here are the best facts and figures Plant Talk can find. 1. Flowering plants (Angiospermae) dominate the contemporary flora of the Earth and constitute virtually all terrestrial vegetation. There are an estimated 250,000 species, with the greatest diversity in the moist tropics. Most Plant Facts will be on flowering plants, but all other types of plant will be covered also. 2. The orchids (Orchidaceae) have more species than any other family of flowering plants with 25,000-35,000 species recognized, mostly in the tropics. Although some species do remain to be discovered, the difference between these estimates is mostly one of different taxonomic concepts.
3. It is likely that 10 to 15% of the Earth's flowering plants have not yet been described. Most will be in the moist tropics, especially remote parts of Latin America.
source: http://www.plant-talk.org/93.htm
