Reassessment of the generic limits for Hydnellum and Sarcodon (Thelephorales, Basidiomycota)

Abstract. DNA sequences from the nuclear LSU and ITS regions were used for phylogenetic analyses of Thelephorales with a focus on the stipitate hydnoid genera Hydnellum and Sarcodon. Analyses showed that Hydnellum and Sarcodon are distinct genera but that the current division, based on basidioma texture, makes Sarcodon paraphyletic with respect to Hydnellum. In order to make genera monophyletic several species are moved from Sarcodon to Hydnellum and the following new combinations are made: Hydnellumamygdaliolens, H.fennicum, H.fuligineoviolaceum, H.fuscoindicum, H.glaucopus, H.joeides, H.lepidum, H.lundellii, H.martioflavum, H.scabrosum, H.underwoodii, and H.versipelle. Basidiospore size seems to separate the genera in most cases. Hydnellum species have basidiospore lengths in the range 4.45−6.95 µm while the corresponding range for Sarcodon is 7.4−9 µm. S.quercinofibulatus deviates from this pattern with an average spore length around 6 µm. Neotropical Sarcodon species represent a separate evolutionary lineage.