The genus Dentipratulum (Russulales, Auriscalpiaceae): comparative morphology and SEM imaging spore ornamentation split one into three species

The family Auriscalpiaceae (Russulales) includes species forming pileate, stipitate-pileate, effused-reflexed, and resupinate basidiomata. The resupinate basidiomata are characteristic only for the genus Dentipratulum, described to accommodate Dentipratulum bialoviesense, found in the BiaowieA 1/4a Primeval Forest in Poland and later reported from several locations in Eurasia. The materials assigned to this genus were revised and three distinct morphospecies were detected, including Dentipratulum bialoviesense s. str. and two new species, Dentipratulum khuranae from India and Dentipratulum crystallinum from the Kuril Islands and France. The concept of the genus Dentipratulum is emended to include characters omitted in the original diagnosis (stem-like base of spines, rudimentary subiculum) and found in the novel species (presence of naked or encrusted leptocystidia). All Dentipratulum species are illustrated with pictures of basidiomata, line drawings of micro-morphological characters, and scanning electron microscopy (SEM) micrographs of basidiospores. A key to the genus is provided.