Pluteus squarrosus, a new species of Pluteus section Celluloderma from northeast China

27 June 2019

Hosen, Dr. Md. Iqbal; Liang, Xishen; Xu, Jiang; Li, Tai-Hui

Pluteus squarrosus from northeast China (Liaoning Province) is described as a new species. It is characterized by a squarrose pileus, a dull white to grayish white pruinose stipe that surface covered by caulocystidial elements, nearly globose to subglobose basidiospores 5.5–6.5 × 5–6 µm, mostly fusoid pleurocystidia, and a trichoderm to trichohymeniderm pileipellis. Data from the nuclear ribosomal internal transcribed spacer (ITS) region shows that this species is nested in Pluteus sect. Celluloderma, and it appears as sister to P. hirtellus. The description is accompanied by color photographs of the basidiomata and line drawings of the main microscopic features. The new species is compared with closely related taxa of Pluteus, and its phylogenetic placement is also assessed.