They are found in the Compoeitae (Cickoriaceae), Campanulaceae, Papaveraceae, Loheliaceae, Papayaceae, in some Aroideae and Musaceae, and in Euphorbiaceae (Manihot, Ilevea).
Cactaceae, Euphorbiaceae), of parasites, and of saprophytes.
Amongst arboreous families Leguminosae and Euphorbiaceae are prominent; Hevea belonging to the latter is widely distributed in various species in the Amazon basin, and yields Para and other kinds of rubber.
The principal orders, arranged according to their numerical importance, are as follows: - Leguminosae,Rubiaceae, Orchidaceae, Compositae, Gramineae, Euphorbiaceae, Acanthaceae, Cyperaceae and Labiatae.
Euphorbiaceae and Scrophulariaceae and Orchidaceae are universally present, the last in specially large proportions.