Investigating floral morphology in the order Geraniales, Jeiter et al. present data to demonstrate that even the most disparate floral morphologies are derived from a common origin, sharing a basic pentamerous and pentacyclic organisation with an obdiplostemonous androecium and receptacular nectaries associated with the antesepalous stamens.
Floral morphology of the Geraniales shows a high degree of similarity, despite divergence in detail. The variations are predominantly lineage specific, with individual apomorphic characteristics such as zygomorphy or a reduced number of nectaries having arisen several times independently.
Jeiter, J., Weigend, M., & Hilger, H. H. (2016). Geraniales flowers revisited: evolutionary trends in floral nectaries. Annals of Botany, 119(3), 395–408. https://doi.org/10.1093/aob/mcw230