LAUSR

Abstract Two new species of Protium (Burseraceae) are described and illustrated: Protium aguilarii sp. nov., from the Pacific slope of the Osa Peninsula, Puntarenas Province, Costa Rica; and Protium hammelii sp. nov., from wet forests on the Caribbean slopes of Nicaragua and Costa Rica. In addition, Protium brenesii comb. nov., is proposed as a new combination based on Trichilia brenesii, a name that was based on a specimen collected with flowers in the mountains near San Ramón, Alajuela Province, Costa Rica. It is compared with Protium costaricense, a similar species with which it has been confused for more than 90 years. Finally, illustrations and specimen citations are provided for all the aforementioned taxa, and some others with which they have been confused.