Teratological organisms originate from developmental anomalies, and exhibit structures and a body organization that deviate from the species standard. In plants, teratological forms are often of horticultural interest. However, besides their aesthetic value, these monsters give essential clues about the formation of the wild-type groundplan. We focus on flower terata, which can be affected in their sterile and/or fertile organs, with special emphasis on the Ranunculaceae. The diversity of perianth shapes and organizations in flowers of this family is huge, and is even increased when anomalies occur during organo- and/or morphogenesis. In order to galvanise research on Ranunculacean flower terata, which has been overlooked since the middle of the 20th century, we provide the necessary material to inspire future studies in this field. We (I) recount the history of the science of flower teratology, (II) review records of flower terata in the buttercup family, (III) propose a system to classify the changes affecting canonical development, (IV) synthesize key studies on the developmental genetics of the flower terata with a focus on Ranunculaceae, and (V) address the issue of their evolutionary potential. We expect Ranunculaceae species to become model organisms in flower teratology studies, focusing on morpho-anatomy as well as on evo-devo or evolutionary ecology.