Four new species of Inocybe (Agaricales) with pleurocystidia and nodulose spores are recorded from a remote region of rain forest in Guyana, in northeastern South America. All four species of Inocybe occur in association with the arborescent legume genus, Dicymbe (Caesalpiniaceae, tribe Amherstieae). This constitutes the first report of a legume host genus with Inocybe in the neotropics. The new species are I. ayangannae, I. epidendron, I. lilacinosquamosa and I. pulchella. A dichotomous key, morphological descriptions, illustrations, taxonomic commentary, and a discussion of Inocybe in the tropics, are provided.