Contributions towards a monograph of Phoma (Coelomycetes) — IV. Section Heterospora: Taxa with large sized conidial dimorphs, in vivo sometimes as Stagonosporopsis synanamorphs

The new section Heterospora is proposed for Phoma species producing not only relatively small, mainly aseptate conidia, but also distinctly larger conidia, which may become 1- or more septate: ‘ascochytoid-stagonosporoid’. The majority of the conidia are always phomoid in vitro, but in vivo they may be predominantly large and septate, synanamorphs being therefore referred to Stagonosporopsis Died. The heterosporous species are described in vitro, with additional data on the conidial morphology in vivo. An addendum deals with eight species from other sections which display a similar conidial dimorphism. Five new species and four new combinations have been proposed: Phoma actaeae spec. nov., Phoma alectorolophi spec. nov., Phoma nigripycnidia spec. nov., Phoma subboltshauseri spec. nov. and Stagonosporopsis dennisii spec. nov.; Phoma dennisii var. oculo-hominis (Punith.) comb. nov., Stagonosporopsis aquilegiae (Rabenh.) comb. nov., Stagonosporopsis bohemica (Kabát & Bubák) comb. nov. and Stagonosporopsis nigripycnidiicola (Ondřej) comb. nov. Indices on host-fungus and fungus-host relations and a key to cultural characteristics are included as well as short comments on their ecology and distribution.