Epidendroideae/Definition

It is the largest subfamily of Orchidaceae, with three quarters of all known species, split into several tribes and subtribes, encompassing more than five hundred genera and about twenty thousand species distributed almost all over the world, except in the dryer deserts and polar areas; known for being orchids with coherent pollen forming pollinia and with one incumbent anther only, or with the anther bent back, but then with clearly plicate leaves and roots hardly ever fleshy.