Amanoa (Phyllanthaceae, Phyllanthoideae) has a pantropical distribution with its center of diversity in the Amazon Basin, but it has not received a recent taxonomic revision. This paper aims to treat the taxonomy of the genus, with emphasis on the Brazilian species. Collections in Brazilian and foreign herbaria were examined under stereomicroscopy with the dissection of vegetative and reproductive organs, and species were re-described and illustrated. The following species were studied: A. almerindae, A. congesta, A. cupatensis, A. glaucophylla., A. gracillima, A. guianensis, A. nanayensis, A. neglecta, A. oblongifolia, A. pubescens, and A. sinuosa. Amanoa pubescens is reestablished and illustrated for the first time. For A. glaucophylla the pistillate flower and illustration are presented for the first time, as well as the staminate flower for A. almerindae, the pistillate flower for A. oblongifolia, and the floral bud and pistillate flower for A. sinuosa. New locality records: Amanoa almerindae for Pará, Amanoa cupatensis for Acre, A. glaucophylla for Pernambuco and Bahia, A. guianensis for Pernambuco and Sergipe, A. neglecta for Brazil (Amapá), A. oblongifolia for Acre and Bahia, A. pubescens for Brazil (Amazonas), and A. sinuosa for Amapá and Pará. Monoecism in A. glaucophylla is registered.
Amanoineae; Euphorbiaceae; Phyllanthoideae
