MYCOTAXON Volume 112, pp. 103–141 April–June 2010 Type studies and nomenclatural revisions in Parasola (Psathyrellaceae) and related taxa László G. Nagy 1* , Csaba Vágvölgyi 1 & Tamás Papp 1 * cortinarius2000@yahoo.co.uk 1 Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Közép fasor 52., Szeged, H-6726, Hungary Abstract — Basidiomycetes belonging in the genus Parasola and some satellite taxa have been revised on the basis of type studies and original diagnoses. As a result of an extensive taxonomic survey, 34 names affiliated with Parasola (formerly Coprinus subsections Glabri and Auricomi) have been identified. Type materials of 15 taxa have been found in various herbaria and examined. ese taxa are described and their basidiospores, basidia, cheilocystidia, pleurocystidia, and pileipelli illustrated. e results support P. leiocephala as a synonym of P. lactea. An epitype for P. plicatilis and a neotype for P. misera are designated and illustrated in detail. Parasola auricoma is lectotypified. Pseudocoprinus besseyi and C. elongatipes are synonymized with P. auricoma. e type of P. galericuliformis represents an immature P. lactea. Coprinus plicatilis var. filopes is a later synonym of P. lactea. C. longipes and C. rimosus are synonymized with P. schroeteri, while Pseudocoprinus brunneolus belongs to P. lactea. Where possible, our conclusions were confirmed by molecular phylogenetic analyses. Key words —synonymization, deliquescence Introduction e genus Parasola Redhead et al. (formerly Coprinus subsection Glabri and Auricomi) comprises coprinoid taxa that lack veils and caulocystidia and have parasol-like, non-deliquescent pilei (Doveri 2004, Orton & Watling 1979, Redhead et al. 2001, Uljé & Bas 1985). Nagy et al. (2009) have recently referred to the process of fruitbody maturation observed in Parasola, which differs from both “true” deliquescence and non-deliquescence, as “collapsing”, in order to avoid confusion with non-deliquescent coprinoid and Psathyrella taxa. Although many widely distributed, well-known taxa belong here, such as P. plicatilis (Curtis) Redhead et al. or P. leiocephala (P.D. Orton) Redhead et al., taxonomic delimitation is still problematic and much confusion surrounds most species. Redhead et al. (2001) recognized 18 taxa in the genus Parasola, resurrecting a number of taxa forgotten in the recent literature, such as Coprinus mirabilis,