The Brazilian tree Goniorrhachis marginata is the only species of its genus in the bean family (Leguminosae) with striking flowers consisting of a long floral tube and regular corolla redolent of the rose family. Prenner and Cardoso study floral development with a scanning electron microscope and analyse the results in a broad phylogenetic context.
Key observations were that the 4-merous calyx has resulted from complete loss of one sepal and that formation of the regular corolla originates from a typical caesalpinioid pattern with the upper petal innermost (ascending aestivation) and the young style bending away from the inflorescence axis. The authors propose a new synapomorphy for the clade further to an extensive dataset analysis showing that abaxial bending styles characterise all major lineages of Detarioid legumes
Prenner, G., & Cardoso, D. (2017). Flower development of Goniorrhachis marginata reveals new insights into the evolution of the florally diverse detarioid legumes. Annals of Botany, 119 (3), 417-432 DOI: 10.1093/aob/mcw223