This species is undoubtedly a widespread saprobic hyphomycete commonly isolated from indoor environments. Morphologically it is comparable with C. cladosporioides (Fig. 1, clade 66) but C. delicatulum (Fig. 1, clade 44) differs from the latter species in having 0−1-septate intercalary conidia and secondary ramoconidia, only a few conidia in the terminal unbranched part of conidial chains, shorter often slightly geniculate conidiophores and shorter secondary ramoconidia. Cladosporium westerdijkiae (Fig. 1, clade 43) is the closest relative in the tree but can be distinguished from C. delicatulum by usually aseptate and somewhat longer ramoconidia and secondary ramoconidia.