Advances in the knowledge of the Inocybe mixtilis group (Inocybaceae, Agaricomycetes), through molecular and morphological studies

Abstract

Inocybe mixtilis constitutes a complex of species characterized by nodulose-angulose spores, absence of cortina and a more or less bulbous marginate stipe that is not darkening when desiccated. In order to elucidate species limits within the I. mixtilis complex, an ITS-RPB2 phylogeny was performed and interpreted using morphological and ecological characters. Six supported clades were obtained in our analyses that correspond to I. mixtilis, I. subtrivialis, and four new species to science: I. ceskae, I. johannis-stanglii, I. nothomixtilis and I. occulta. Species within this complex can be morphologically recognized through a unique combination of morphological characters, such as the spore shape, cystidial length and shape, presence and development of the velipellis and pileus colour and viscidity. Nevertheless, those characters overlap, especially among I. mixtilis, I. ceskae and I. occulta, and intermediate collections are therefore more reliably identified through ITS-sequencing. Two species, I. ceskae and I. occulta are present in both North America and Europe, while the rest are so far only known in Europe, or Europe and Asia (I. mixtilis). All species, except I. johannis-stanglii, seem to be able to establish ectomycorrhizal association both with conifers and angiosperms. Descriptions, colour illustrations and a key to all known species in the I. mixtilis group are provided.

A fresh outlook on the smooth-spored species of Inocybe: type studies and 18 new species

“…Even though the nodulose-spored species of Inocybe are still far from being 'done' and not all taxa have been re-studied yet by morphological and molecular means, in Europe, in the last decade, great progress has been made (see for instance Kokkonen 2011;Esteve-Raventós et al 2015, Esteve-Raventós et al 2016, Esteve-Raventós et al 2018Larsson et al 2018b;Cripps et al 2019b;Bandini et al 2019aBandini et al , 2020a. Although some studies have been published on smooth-spored species (e.g.…”

Four new nodulose-spored species of Inocybe (Agaricales) from West Africa

“…2008 , Horak et al . 2015 , Matheny & Bougher 2017 , Matheny et al 2017 , Latha & Manimohan 2017 , Esteve-Raventós et al . 2018 , Bandini et al 2019 , Cripps et al .…”