A phylogenetic assessment of Endocalyx (Cainiaceae, Xylariales) with E. grossus comb. et stat. nov.

The phylogenetic affinities of four representative Endocalyx taxa at the species and variety levels are studied based on materials collected on different palm hosts in Japan and the states of Hawaii and Texas, USA. They include specimens and their isolates belonging to E. cinctus, E. indumentum, E. melanoxanthus var. grossus, and E. melanoxanthus var. melanoxanthus. Phylogenetic analyses of nuclear ribosomal DNA sequence data (ITS-LSU nrDNA) confirmed that Endocalyx belongs to the order Xylariales (Sordariomycetes) where all species and varieties treated form a strongly supported monophyletic lineage within the family Cainiaceae. They were also phylogenetically well resolved and consistent with their morphological and ecological circumscription. Species status is proposed for E. melanoxanthus var. grossus under the name E. grossus comb. et stat. nov. on the basis of its distinct morphological, molecular, cultural, and ecological characteristics. The putative placement of Endocalyx within the family Apiosporaceae (Amphisphaeriales), based on the presence of basauxic conidiophores, is rejected considering that all species treated clustered within the distant Cainiaceae (Xylariales). This characteristic mode of conidiophore elongation is determined to have evolved independently within distantly related ascomycetous lineages. Novel morphological and cultural features of Endocalyx taxa based on new isolates are described and commented. The recently described E. metroxyli is reduced to a synonym with E. melanoxanthus.