Conidiomata

Abstract: A detailed description is provided of the coelomycetous fungus causing dogwood anthracnose on Cornus florida, C. kousa and C. nuttallii in North America. Conidiomata are acervular and subcuticular ...

Abstract: Coelomycete is a general term used for asexual fungi which produce conidia in fruiting bodies: pycnidial, acervular, cupulate, pycnothyria or stromatic conidiomata. The group contains numerous plant pathogenic, saprobic and endophytic species associated with a wide range of hosts. Traditionally, morphological characters and host associations have been used as criteria to identify and classify coelomycetes, and this has resulted in a poor understanding of their generic and species boundaries. DNA based taxonomic studies have provided a better outlook of the phylogenetic and evolutionary trends in coelomycetes. However, the present outcomes represent only a preliminary step towards the understanding of coelomycetes. Many genera have not been revisited since they were first described. The present study revises the classification of the hyaline-spored coelomycetes and provides a modern taxonomic framework based on both morphology and phylogeny. In total, 248 genera were investigated, of which less than 100 are known to have sequence data. Multi-locus sequence data analyses of 28S nrDNA, 18S nrDNA, ITS, RNA polymerase II second largest subunit (rpb2), and part of the translation elongation factor 1-alpha gene (tef1) and β-tubulin (tub2) gene regions were analysed. As a result, three new genera and 23 new species are introduced. In addition, three new links between sexual and asexual genera are provided. There are 138 genera that lack sequence data, and these are treated as Ascomycota, genera incertae sedis. Line drawings and descriptions are provided based on the examination of types and fresh collections and on the literature.

Abstract: In this study we accept 25 families in Diaporthales based on phylogenetic analyses using partial ITS, LSU, rpb2 and tef1-α gene sequences. Four different families associated with canker and dieback of tree hosts are morphologically treated and phylogenetically compared. These include three new families (Diaporthostomataceae, Pseudomelanconidaceae, Synnemasporellaceae), and one new genus, Dendrostoma (Erythrogloeaceae). Dendrostoma is newly described from Malus spectabilis, Osmanthus fragrans and Quercus acutissima having fusoid to cylindrical, bicellular ascospores, with three new species namely D. mali, D. osmanthi and D. quercinum. Diaporthostomataceae is characterised by conical and discrete perithecia with bicellular, fusoid ascospores on branches of Machilus leptophylla. Pseudomelanconidaceae is defined by conidiogenous cells with apical collarets and discreet annellations, and the inconspicuous hyaline conidial sheath when mature on Carya cathayensis, compared to morphologically similar families Melanconidaceae and Juglanconidaceae. Synnemasporellaceae is proposed to accommodate fungi with synnematous conidiomata, with descriptions of S. toxicodendri on Toxicodendron sylvestre and S. aculeans on Rhus copallina.