The reported acetate-derived labelling of the fungal naphthalene γ-pyrone fonsecin, two streptomycete dodecaketide αpyrones TW93f and TW93g, and the streptomycete phenanthraquinones piloquinone, murayaquinone and haloquinone appear to be exceptions to the generalisation that fungi and streptomycetes produce fused-ring aromatic polyketides by different modes of cyclisation. A review of their 1) originally assigned formulae, 2) [ C ]acetate-derived labelling patterns, and 3) modes of cyclisation leads to the recognition of feasible alternative chemical structures or biosynthetic pathways, which are in accord with the originally proposed classification system.