Original data on leaf crystals and stomatal types in 25 genera of Melastomataceae are presented, and discussed with reference to the classification of the family as modified by Van Vliet et al. (1981, this issue). The heterogeneity of the abolished subfamily Astronioideae is confirmed and a separation of Pternandra from the Astronieae is also justified on the basis of leaf anatomical data. The Astronieae are characterized by large styloids and predominantly anomocytic stomata; this combination of characters also occurs in part of the Melastomatoideae (especially the Miconieae). Most other Melastomatoideae are characterized by polocytic to diacytic stomata and druses. The subfamilies Memecyloideae and Crypteronioideae remain rather heterogeneous leaf anatomically, but the evidence can be interpreted in support of mutual affinities.