Possible evidence for reinforcement in the geographical distribution and hypothetical pollinaria attachment sites (on a large sphingid hawkmoth) of two angraecoid clades with divergent column exsertion lengths in tropical Africa. Aerangis gracillima (yellow triangles) is closely allied to A. stelligera (blue triangles), while Ypsilopus amaniensis (blue diamonds) is closely related to Y. schliebenii (yellow diamonds). An extremely elongated Barombia-type column is present in A. gracillima and Y. schliebenii. The three isolated collections of Y. amaniensis in Zimbabwe are here assigned to Ypsilopus zimbabweensis (white diamonds). Photos by Murielle Simo-Droissart (A. gracillima), Bart Wursten (A. stelligera), Guido van Asten (Y. amaniensis), and Russell Hutton (Y. schliebenii).