The family Gelatinodiscaceae and genus Ascocoryne represent diverse lineages in Helotiales ( Ascomycota , Leotiomycetes ) that lack well-sampled phylogenies and taxonomic study. Our research objectives were to 1) determine whether certain genera that lacked DNA sequence data or had uncertain phylogenetic placement — Clathrosporium , Phaeangellina , Skyathea , and Xerombrophila — belonged to Gelatinodiscaceae , 2) estimate species richness and describe new species in Ascocoryne , 3) determine if morphological characteristics delineate intrageneric clades in Ascocoryne , and 4) test the mitochondrial tricarboxylate transport protein ( CTP ) as an alternative DNA barcode in Ascocoryne . We made 83 Gelatinodiscaceae collections primarily from the midwestern United States, examined 61 collections previously deposited in herbaria, and generated DNA sequence data for seven loci (18S, ITS, 28S, EF1 , RPB1 , RPB2 , CTP ) from these collections. We found that Skyathea , Xerombrophila , and up to four other unnamed, putative genera belong to Gelatinodiscaceae , while Clathrosporium and Phaeangellina are excluded. Up to 37 putative undescribed species-level clades or single isolates are present in Ascocoryne , in addition to the nine previously described species and four newly described ones here: Ascocoryne diminutiva , A. fibrosa , A. neoinflata , and A. wilsoniae . Additionally, descriptions for two unnamed species similar to A. cylichnium are given, a preliminary description of the sexual morph of A. laurisilvae is provided, and A. trichophora is synonymized with A. vinosa . Four main clades are found in the genus Ascocoryne . The size of lipid bodies in living ascospores, the arrangement of conidia borne on ascospores, and the presence of calcium oxalate crystals are the most important morphological characteristics for distinguishing among clades. The CTP and ITS loci successfully identified six of six Ascocoryne species tested. This study provides the best-sampled phylogeny of Gelatinodiscaceae and Ascocoryne and highlights unnamed genus- and species-level diversity in this group
Stallman et al. (Thu,) studied this question.