Inocybe tauensis, a new species from the Samoan Archipelago with biogeographic evidence for a Paleotropical origin.

Inocybe tauensis is described as a new species from the island of Ta'u, American Samoa. The species occurs in native littoral forest and is associated with the ectomycorrhizal tree Pisonia grandis. Based on an analysis of nLSU, RPB1, and RPB2 sequence data, I. tauensis appears to be derived from ancestors with a Paleotropical biogeographical distribution. Alternative explanations for the unexpected presence of an Inocybe species in the Samoan Archipelago are discussed.

Does secotioid inertia drive the evolution of false-truffles?

Secotioid inertia is a model implemented to explain the prevalence of highly derived false-truffles with no obvious connection to the Homobasidiomycetes. The model accommodates the apparent lack of epigeous sister taxa for some highly derived hypogeous lineages by assuming that gasteromycetation in some fungi leads to the extinction of their epigeous sister population. The derived state of some hypogeous lineages suggests that they arose early in the evolution of Homobasidiomycetes and that those groups were subject to conditions that favoured hypogeous lineages such that the hypogeous fruit body form became the predominant form for some lineages. The directional selection component of secotioid inertia, termed secotioid drive, led to the extinction of their epigeous sister taxon. Morphological and molecular data from Russulaceae are used to model the evolutionary stages of secotioid inertia. The resulting phylogenetic results are compared with data from the order Leucogastrales, and the genus Destuntzia. The implications of secotioid drive are discussed with reference to gasteromycete phylogenetics, evolution, and conservation. Specifically, secotioid inertia can be used to account for reversals in fruit body morphology and instability in mycorrhizal formation.

The phylogenetic placement of the Leucogastrales, including Mycolevis siccigleba (Cribbeaceae), in the Albatrellaceae using morphological and molecular data.

The morphology of many hypogeous fungi converges on a homogeneous reduced form, suggesting that disparate lineages are subject to a uniform selection pressure. The primary goal of this study was to evaluate the morphology and infer the phylogeny of the Leucogastrales with Mycolevis siccigleba using a Bayesian methodology. A comprehensive morphological assessment was used for an a priori phylogenetic inference to guide the sequencing effort. All structures except spore ornamentation pointed to the Albatrellaceae as the most likely sister taxon. Polyporoletus sublividus, a close relative of Albatrellus, produces ornamented basidiospores with a similar structure to M. siccigleba basidiospores. The ITS from 30 taxa was used for the molecular phylogenetic analysis. P. sublividus was found sister to Mycolevis. Leucophleps spinispora and L. magnata formed a group sister to the Polyporoletus/Mycolevis group, whereas Leucogaster was polyphyletic with respect to the core of the Leucogastrales and sister to A. caeruleoporus. This relationship was expected as previously undescribed chlamydospores produced by members of Albatrellus had a similar morphology to the basidiospores of L. rubescens.