The floral development of Berberidopsis beckleri is compared with its sister species B. corallina to clarify the origins of the pentamerous pentacyclic flower of the core eudicots. Both species are unusual amongst core eudicots in having flowers arranged on short axillary shoots with spiral phyllotaxis and an undifferentiated perianth.
Ronse de Craene suggests that floral evolution in core eudicots proceeded with a progressive reduction of perianth parts linked with a transition to a whorled phyllotaxis. B. beckleri and B. corallina represent prototypes of a gradient shift towards more regular core eudicot flowers with a combination of ancestral and highly specialised features.
Ronse De Craene, L. P. (2017). Floral development of Berberidopsis beckleri – can an additional species of the Berberidopsidaceae add evidence to floral evolution in the core eudicots?. Annals of Botany, mcw241. https://doi.org/10.1093/aob/mcw241