Adelobotrys (Merianieae: Melastomataceae) is a neotropical, primarily Amazonian genus of 23 lianas and eight arborescent species. A cladistic analysis was performed to test the monophyly of Adelobotrys, discover its synapomorphies, and clarify its internal relationships. The results also allowed a preliminary appraisal of generic limits within Merianieae. For the analysis, 117 morphological characters were coded for 53 ingroup taxa (52 of Adelobotrys plus Sarmentaria decora) and 12 outgroup species from the genera Meriania, Graffenrieda, Axinaea, Centronia, Phainantha, Behuria, Huberia, Pachyloma, and Pternandra. The analysis resulted in a single most parsimonious tree. The result suggests that Adelobotrys is polyphyletic. However, species that fall within the original circumscription of the genus form a well-supported monophyletic group. This group of lianoid species with narrow hypanthia; 5-locular ovaries; short fruiting pedicels; urceolate to globose fruiting hypanthia; elongated, winged seeds; and a vestiture of malpighian hairs is here termed Adelobotrys sensu stricto. Several well-defined lineages are recognized within Adelobotrys s.s., although most of them have only weak support. Purported problems persist with circumscriptions of merianean genera, in particular Meriania.