Pseudotulostoma volvatum (Elaphomycetaceae, Ascomycota) from an Amazonian white-sand forest in Brazil: odd and rare in the Neotropics?

Abstract

Pseudotulostoma is a genus described for fungi with stipitate sporocarps that have an exposed gleba and a woody, volvate base. The two species that belong to this genus (P. volvatum and P. japonicum) form unusual epigeous ascomata that are atypical among the hypogeous members of the Elaphomycetaceae. The genus was first described from the Guiana Shield and was suggested to be restricted to rainforests dominated by the ectomycorrhizal tree Dicymbe corymbosa (Leguminosae-Detarioideae). Pseudotulostoma volvatum was also later described from Colombia in association with Pseudomonotes tropenbosii (Dipterocarpaceae- Monotoidea). Here we report a new occurrence of P. volvatum that is also the first occurrence of an ectomycorrhizal Ascomycota fungus in a native host plant in Brazil. The description includes images of the macroscopic and microscopic characteristics, a discussion of the distinctive features, and phylogenetic placement using the nLSU of this fungus among Elaphomyces species. This new collection (third known location) demonstrates that P. volvatum also occurs in a white-sand forest composed of the canopy tree Aldina heterophylla (Leguminosae-Papilionoideae). Thus, we provide additional information regarding P. volvatum that expands its known distribution.