Brevicollum, a new genus in Neohendersoniaceae, Pleosporales.

A new genus, Brevicollum, is established for two new species, B. hyalosporum on Syzygium samarangense and B. versicolor on Volkameria inermis, in Japan. This genus is characterized by the presence of immersed ascomata with an excentric to central, short cylindrical ostiolar neck, thin ascomatal wall, clavate asci with a shallow ocular chamber, and broadly fusiform, hyaline to pale brown ascospores with a sheath. Molecular phylogenetic analyses based on a combined data set of sequences of 18S and 28S nuc rDNA genes and the second largest subunit of RNA polymerase II (RPB2) revealed that Brevicollum is a member of Neohendersoniaceae (Pleosporales, Dothideomycetes). The genera Brevicollum, Crassiparies, Medicopsis, and Neohendersonia are accepted in Neohendersoniaceae. Revised descriptions of Crassiparies and its type species, C. quadrisporus, are provided based on the holotype and a newly obtained specimen and isolate. An asexual morph of C. quadrisporus is reported for the first time. The nuc rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) phylogenetic tree of the newly collected species (B. hyalosporum, B. versicolor, and C. quadrisporus), and the unnamed or provisionally identified endophytic species, suggests a broader distribution of Brevicollum and Crassiparies species.