Holarctic Species in the Pluteus romellii Clade. Five New Species Described and Old Names Reassessed

Abstract

We studied the taxonomy of Pluteus romellii, and morphologically similar Holarctic species in the /romellii clade of section Celluloderma, using morphological and molecular data (nrITS, TEF1-α). Pluteus romellii is lectotypified and epitypified and accepted as an exclusively Eurasian species. Pluteus lutescens and P. pallescens are considered synonyms of P. romellii. Pluteus fulvibadius is accepted as a related, but separate, North American species. Five species in the /romellii clade are described as new to science: two from North America (P. austrofulvus and P. parvisporus), one from Asia (P. parvicarpus), one from Europe (P. siccus), and one widely distributed across the Holarctic region (P. vellingae). Basidioma size, pileus color, lamellae color, basidiospore size, hymenial cystidia shape and size, habitat and geographical distribution help separate the species described here, but in some instances only molecular data allows for confident identification. The current status of P. californicus, P. melleipes, P. romellii var. luteoalbus, P. splendidus, P. sternbergii and P. sulphureus is discussed.

A new species and new records species of Pluteus from Xinjiang Uygur Autonomous Region, China

“…On phylogenetic trees, P. siccus display a close relationship to P. aletaiensis ; morphologically, they are distinctly different, P. siccus ( Ševčíková et al, 2022 ) is distinguishable from P. aletaiensis due to its slightly velvety pileus with a greenish hue, and smaller basidiospores (about 4.6–6.0 × (3.5–)4.5–5.5 µm), the polymorphic cheilocystidia, and grows on decaying wood and geographically distributed in the Russian Far East. P. parvicarpus ( Ševčíková et al, 2022 ) could be distinguished from P. aletaiensis by its sulcate-striate at the margin of pileus, smaller basidiospores (about 4.5–6.0 × 4.2–5.5 µm), solitary on fallen branches of deciduous trees, and geographical distribution in the Russian Far East. P. aletaiensis and P. vellingae ( Ševčíková et al, 2022 ) are both with yellow-brown to brown pileus and similar basidiospores.…”

“…P. parvicarpus ( Ševčíková et al, 2022 ) could be distinguished from P. aletaiensis by its sulcate-striate at the margin of pileus, smaller basidiospores (about 4.5–6.0 × 4.2–5.5 µm), solitary on fallen branches of deciduous trees, and geographical distribution in the Russian Far East. P. aletaiensis and P. vellingae ( Ševčíková et al, 2022 ) are both with yellow-brown to brown pileus and similar basidiospores. P. vellingae has broadly clavate to clavate or ovoid pleurocystidia, and it grows on coniferous or deciduous wood.…”

“…P. fulvibadius differs from P. aletaiensis by its bigger pileus, which reaches 15–50 mm broad, slight to strongly rugose around the center, and translucently striate at the margin. In microfeatures, the pleurocystidia of P. fulvibadius are cylindrical-clavate; the pleurocystidia and the cheilocystidia are covered with an apical cap of amorphous mucilaginous material ( Minnis, 2008 ; Minnis & Sundberg, 2010 ; Ševčíková et al, 2022 ).…”

“…obtained the molecular sequence of P. sternbergii ( ) and verified the position of P. sternbergii in the phylogenetic tree, not in the romellii clade, but in the cinereofuscus clade, therefore, selected collection PRM 154258 as the epitype of P. sternbergii . ( Ševčíková et al, 2022 ). Morphologically, the basidiospores, basidia, pleurocystidia, and stipitipellis of P. aletaiensis and P. sternbergii are similar, while P. sternbergii grows in the stump of Populus.…”

“…Based on BLAST results, morphological similarities, and the related articles ( Menolli, Asai & Capelari, 2010 ; Justo et al, 2014 ; Menolli, Justo & Capelari, 2015 ; Rao et al, 2021a ; Ševčíková et al, 2022 ), ITS and TEF1-α sequences obtained and related to these samples are listed in Table 1 . The ITS and TEF1-α dataset comprised 106 representative sequences showing the highest similarity to Pluteus spp., and two sequences of Volvopluteus michiganensis (A.H.…”