Additions to Hohenbuehelia (Basidiomycota, Pleurotaceae): two new species and notes on H.tristis from northern Thailand.

Two new species and a first geographical record of Hohenbuehelia are described from Thailand. Macroscopic and microscopic descriptions with photoplates, as well as a multigene phylogeny are provided. Hohenbueheliaflabelliformis sp. nov. is recognised by large flabelliform basidiomata, densely villose yellowish-white pileus with white hairs near the point of attachment, basidiospores that mostly are ellipsoid in front view and phaseoliform in side view, the absence of cheilocystidia, and a trichoderm pileipellis. Hohenbuehelialageniformis sp. nov. is characterised by fleshy basidiomata, velutinous pileus with whitish hairs near the point of attachment and the margin, elsewhere pale greyish-yellow and with only sparse white hairs, pale brown to light brown and mucilaginous context, subglobose basidiospores, lageniform cheilocystidia, an ixotrichoderm pileipellis, and the absence of pileoleptocystidia. Hohenbueheliatristis is characterised by small creamy-white, spathuliform basidiomata that are larger than the type subspecies, minutely pubescent pileus with tiny greyish hairs that disappear when mature, leaving the surface glutinous, faintly translucent and shiny, ellipsoid to sub-ellipsoid basidiospores, lecythiform to sublageniform cheilocystidia, and an ixotrichoderm pileipellis. Hohenbueheliatristis is recorded for Thailand for the first time. Based on the polymorphism observed in part of the nrLSU gene, the presence of two divergent lineages within H.tristis is discussed.