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Abstract: The type collections of Hebeloma leucosarx, H. velutipes, H. favrei and H.
lutense, as well as some additional original and historically-relevant material were studied.
The type of H. leucosarx turned out to contain parts belonging to two different taxa;
accordingly, it represents a case of admixture. One element is characterized by clava...
Citations
... N51.27 W0.37, alt. c. 100 m) in mixed woodland under Betula sp. and Salix sp., 15 Oct. 1955, P.D. Orton E 00076300, database record HJB12917: this forms part of a collection labelled as H. leucosarx which was mixed and the part that does not represent H. leucosarx as recently selected by Grilli (2007) Notes -Given the shape of its cheilocystidia, H. lutense clearly belongs to H. subsect. Denudata. ...
Hebeloma subsection Denudata includes the type of H. section Denudata, Hebeloma crustuliniforme, as well as the majority of the taxa commonly included in the Hebeloma crustuliniforme complex. Complementing the work of D.K. Aanen and co-workers, and using refined morphological and molecular methods we were able to recognize further individual taxa within the section. Fifteen species occurring in Europe are assigned to H. subsect. Denudata. Of these, we describe eight species as new, namely H. aanenii, H. aurantioumbrinum, H. geminatum, H. louiseae, H. luteicystidiatum, H. pallidolabiatum, H. perexiguum and H. salicicola. Naucoria bellotiana, a species very similar to H. alpinum is recombined into Hebeloma. A key to Hebeloma subsect. Denudata is provided. We demonstrate that within this subsection there is good overall consistency between morphological, phylogenetic and biological species concepts. In contrast to current opinion, in this group there is little species overlap, particularly when also considering species frequencies, between arctic and alpine floras on one hand and temperate on the other.
Hebeloma velutipes is one of the most common and abundant members of the ectomycorrhizal basidiomycete genus and H. sinapizans is one of its oldest and most commonly recorded species. Using large sample sizes, several loci and the analysis of types, we explored the taxonomy, species limits, distribution and the infrageneric classification of these two species and their relatives. By relying almost exclusively on sequenced material, we were able to attain a marked refinement of species descriptions. Phylogenetic results are congruent with respect to the delimitation of species, but suggest conflicting evolutionary histories of the species phylogeny. Using multi-species coalescent analysis, phylogenetic support for H. sects. Velutipes and Sinapizantia was assessed, finding clear support for H. sect. Sinapizantia but ambiguous results for H. sect. Velutipes. One species, H. subconcolor, previously accommodated in H. sect. Denudata, is placed in H. sect. Velutipes. Hebeloma bulbiferum, so far not considered in systematic treatments, is shown to belong to H. sect. Sinapizantia. Unexpectedly, H. velutipes turned out to be distinct from H. leucosarx. Hebeloma erebium comb. nov., H. celatum sp. nov. and H. quercetorum, formerly treated as a single species (H. quercetorum), are demonstrated to be three taxa that are clearly distinct in molecular terms, even though, morphologically, they can be deceptively similar; H. erebium and H. quercetorum are, moreover, geographically distinct. The morphological characters used to distinguish the ten recognised European species are outlined. Finally, a lectotype and an epitype are designated for H. sinapizans and a lectotype for H. quercetorum.
It is widely recognised that there is no consistent use of the name H. crustuliniforme. The name has been used to represent a number of different taxa and indeed taxa from sections of Hebeloma that are morphologically and molecularly well separated. The holotype of H. crustuliniforme is plate 308 Bulliard from 1787 and while it can be interpreted, no such interpretation can be without ambiguity. It is clear from existing literature that modern authors have applied numerous different interpretations to this name and no real consensus exists. Indeed it appears that at various times most of the medium to large species within both sections Denudata and Velutipes Vesterh. have been referred to as H. crustuliniforme. Within this paper an epitype is selected for H. crustuliniforme in order to give the taxon a precise meaning and a detailed species description is given. Molecular data combined with the results of intercompatibility tests of Aanen and Kuyper published earlier support the definition of H. crustuliniforme adopted in this paper as a distinct taxon and as a biological species. We strongly recommend that this taxon be referred to as Hebeloma crustuliniforme (Bull.) Quél. emend. Vesterh., U. Eberh. & Beker in order to emphasise that it is the specific taxon rather than the complex to which it is being referred.
