The present paper continues a series of comprehensive taxonomic treatments of cercosporoid fungi (formerly Cercospora s. lat.), belonging to the Mycosphaerellaceae (Ascomycota). The fourth contribution of this series initiates treatments of cercosporoid fungi on dicots and comprises species occurring on hosts belonging the the families Acanthaceae, Actinidiaceae, Adoxaceae, Aizoaceae, Altingiaceae, and Amaranthaceae. The species are described and illustrated in alphabetical order under the particular cercosporoid genera, supplemented by keys to the species concerned. A detailed introduction, a survey of currently recognised cercosporoid genera, a key to the genera concerned, and a discussion of taxonomically relevant characters were published in the first part of this series. The following taxonomic novelties are introduced: Cercospora blepharidicola nom. nov., C. celosiigena sp. nov., C. justiciae-adhatodae sp. nov., C. justiciigena nom. nov., C. sambucicola nom. nov., C. thunbergiigena nom. nov., Cercosporella pseudachyranthis comb. nov., Pseudocercospora cyathulae comb. nov., P. depazeoides comb. nov., P. varia var. viburni-sargentii var. nov., P. viburnicola sp. nov., P. viburni-erosi sp. nov., and P. viburni-nudi sp. nov.

Ascomycota, Cercospora s. lat., hyphomycetes, taxonomy