Re-Valuation of the Taxonomic Status of Species within the Inocybe similis Complex.

The taxonomy of Inocybe similis and closely allied species is addressed using morphological and molecular data (nrITS and nrLSU DNA). The holotypes of I. chondrospora and I. vulpinella and the isotype of I. immigrans were studied and sequenced. Our results suggest the synonymy between I. similis and I. vulpinella as well as that between I. chondrospora and I. immigrans.

Holarctic Species in the Pluteus podospileus Clade: Description of Six New Species and Reassessment of Old Names.

We studied the taxonomy of Pluteus podospileus and similar species using morphological and molecular (nrITS, TEF1-α) data, including a detailed study of the type collections of P. inflatus var. alneus, Pluteus minutissimus f. major, and P. granulatus var. tenellus. Within the P. podospileus complex, we phylogenetically confirmed six species in Europe, five in Asia, and eight in North America. Based on our results, we recognize P. seticeps as a separate species occurring in North America, while P. podospileus is limited to Eurasia. We describe six new species and a new variety: P. absconditus, P. fuscodiscus, P. gausapatus, P. inexpectatus, P. millsii, and P. notabilis and its variety, P. notabilis var. insignis. We elevate Pluteus seticeps var. cystidiosus to species rank as Pluteus cystidiosus. Based on the holotype of P. inflatus var. alneus, collections of P. inflatus identified by Velenovský, and several modern collections, we resurrect the name P. inflatus. Based on molecular analyses of syntypes of Pluteus minutissimus f. major and a holotype of Pluteus granulatus var. tenellus, we synonymize them under P. inflatus. We also increase our knowledge about the morphology and distribution of P. cutefractus.

Pluteus insidiosus Complex, Four New Species Described and Pluteus reisneri Resurrected.

We studied the taxonomy of Pluteus insidiosus and similar species using morphological and molecular (nrITS, TEF1-α) data, including a detailed study of the type collection of P. insidiosus. Based on our results, we recognize five species in this group: P. insidiosus sensu stricto and four other taxa: P. assimilatus; P. farensis; P. flavostipitatus; and P. pseudoinsidiosus; described here as new. All these taxa are distinct from each other based on molecular data, but some of them are semi-cryptic based on morphology and co-occur in the Palaearctic region. An additional molecular lineage, phylogenetically separates from the P. insidiosus complex, but with many morphological similarities, was recognized in the molecular phylogenies. Based on the revision of available type collections, the name Pluteus reisneri Velen., was adopted for this Clade. Pluteus reisneri was validly published in 1921, but it has barely been used since its original description. A modern epitype, with molecular data, was selected for P. reisneri.

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

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.