Taxonomy and phylogeny reveal new species of Volvariella (Volvariellaceae, Agaricales) and Volvopluteus (Pluteaceae, Agaricales) from eastern India

Abstract

Volvariella areolavolvata sp. nov. and Volvopluteus fibrillobrunneus sp. nov. are introduced and illustrated from West Bengal, eastern India, based on detailed morphological observations and molecular phylogenetic analyses. Morphologically, V. areolavolvata is distinguished by its large-sized basidiomata with a pileus covered by conspicuous silky fibrils, becoming slightly yellowish at the center with age; the presence of a volva with a distinctive, externally areolate cracked surface; oval to ellipsoid basidiospores with a mean value of 7.75 × 4.91 μm; mostly lageniform cheilocystidia, 63–131 × 21–37 μm; and broadly clavate pleurocystidia with a rounded apex, 44–56 × 13–17 µm.

Volvopluteus fibrillobrunneus is characterized by a pileus with light brown to greyish-brown fibrils; ellipsoid to elongate basidiospores (mean 9.85 × 6.30 μm); mostly clavate cheilocystidia measuring 34–72 × 15–29 μm; and rostrate pleurocystidia with prominent apical appendages, 53–75 × 14–21 µm. Phylogenetic analyses based on combined nrITS and nrLSU sequence data support the recognition of both taxa as distinct species within Volvariella and Volvopluteus, respectively, forming well-supported clades clearly separated from their closest species.

Detailed morphological descriptions, field photographs of the collected basidiomata, comparisons with morphologically similar taxa, and phylogenetic analyses based on the combined nrITS and nrLSU sequence datasets are provided.