The genus Mitrephora (Annonaceae) comprises 47 species of small to medium-sized trees, growing in tropical lowland and submontane forests throughout Southeast Asia. The centers of diversity lie in Borneo, where there are 12 species, and the Philippines, where there are 11 species. The flowers are pendent and hermaphroditic, with two whorls of petals, of which the outer petals are larger. The inner petals are apically con-nivent over there productive structures, forming a partially enclosed pollination chamber with small apertures between the basal claws of the petals that enable entry by pollinators. A field study of the pollination ecology of M. heyneana in Sri Lanka (the first such study for the genus) revealed pollination by small nitidulid beetles, although it is possible that other species may be fly-pollinated.