Three new species of Inosperma (Inocybaceae, Agaricales) from western Sichuan, China, based on morphological and multigene phylogenetic evidence

Despite extensive mycological records from western Sichuan, China, no species of Inosperma have been reported from this area. In the present study, we describe three new Inosperma species from the subalpine regions of western Sichuan, namely, I. fibrifugum, I. glomerisquamulosum, and I. lilacinifolium. Phylogenetic analysis based on sequences of ITS, nrLSU, and rpb 2 indicates that these species form three distinct, strongly supported subclades.

Specifically, I. fibrifugum and I. glomerisquamulosum fall within the Cervicolores clade, sister to I. mucidiolens and I. turietoense, respectively. I. lilacinifolium belongs to the Maculatum clade, clustering with I. quietiodor and I. shawarense. Inosperma fibrifugum is characterized by a fibrillose to scaly, fuscous brown pileus with scales persisting only on the umbo at maturity and a context that bruises reddish-brown.

Inosperma glomerisquamulosum is characterized by small basidiomata with a yellowish-brown pileus covered with distinct scales, an indistinct odor, and the absence of caulocystidia. Inosperma lilacinifolium is characterized by a radially fibrillose, grayish-brown pileus and lilac lamellae, along with the presence of arachnoid veil remnants when young. A key to the Chinese species of Inosperma is provided.