Leucoagaricus taniae (Agaricaceae) is described as new to science. It was found growing in sand at Armação beach on Santa Catarina Island in Southern Brazil covered by sand among Canavalia rosea (Fabaceae) and Cyperus pedunculatus (Cyperaceae). The new species has a cream white pileus that is up to 50 mm in diameter and exudes golden drops when fresh. The stipe is up to 60 mm height, with rhizomorphs at the end of the volvate base. Photographs of fresh basidiomes in situ and illustrations of the main micromorphological features are presented. A molecular-phylogenetic analysis that includes the species is also presented.

Leucoagaricus nzumbae sp. nov. (Agaricaceae) is described based on morphological and molecular data from Teresópolis, Rio de Janeiro, Brazil. This species is characterized by the delicate small basidiomes that turn completely lilac when dried, brownish color of the pileus surface, and trichodermal elements with intracellular and parietal brown pigments of the pileus covering. A lectotype and an epitype are designated for Leucoagaricus gongylophorus, a symbiotic fungus of leaf-cutting ants. Full description, nomenclatural notes, and illustrations of fresh basidiomes in situ and of the main macro-and micromorphological features of both species are provided.