The present book gives extensive descriptions and photographs of the leaf venation patterns of 485 (out of c. 3000-4750) species representing 79 (out of c. 215- 240) genera of the Melastomataceae and 70 (out of c. 360) species belonging to 3 (out of 4) genera of the closely allied Memecylaceae. The descriptions are followed by a key to the four main groups and 40 patterns distinguished. This key, which is illustrated by the first ten plates, is the only place where the patterns are defined; under the descriptions they are not even mentioned. The patterns are described per genus. If there is more than one type in a genus these different types are all fully described separately and marked by a capital, without any reference to the patterns given at the end. Under each description is/are mentioned the species, under each species the one collection number of a leaf on which the description has been based. Each genus is ended up by an often extensive discussion. Nearly every specimen used is illustrated by a photograph of the cleared leaf.