Xenochalara, a new genus of dematiaceous hyphomycetes for chalara-like fungi with apical wall building conidial development

Ceratocystis autographa Bakshi is unusual amongst the ophiostomatoid fungi in that it produces two distinct anamorphs, typifying different teleomorph genera. A chalara-like anamorph characteristic of the genus Ceratocystis se nsu stricto Ellis & Halst. and a Sporothrix Hektoen & C.F. Perkins anamorph typical of the genus Ophiostoma Syd. & P, Syd., have been described for th e fungus. In a recent study. an isolate resembling C. autographa, that was collected from Juniperus L., was shown to have a different type of conidiog enesis to that of typical species of Chalara (Corda) Rabenh. Furthermore, c ycloheximide tolerance and the presence of rhamnose in the cell walls of th is isolate also suggested that it was more closely related to Ophiostoma th an to Ceratocystis s. str. Parsimony analysis of ribosomal DNA sequence dat a in this study showed that this isolate formed a monophyletic group, disti nct from Ceratocystis isolates and from Ophiostoma ulmi (Bulsman) Nannf. Th e chalara-like anamorph from Juniperus is also distinct from typical Chalar a anamorphs of Ceratocystis s. str. in that it produces conidia from phiali des via apical wall building, in contrast to the ring wall building typical of Chalara species. We. therefore, propose the establishment of a new genu s. Xenochalara gen. nov., for this and other chalara-like species producing conidia by apical wall building.