Data from: Intraspecific divergence and convergence of floral tube length in specialized pollination interactions

Floral tubes are often thought to be the consequence of adaptive specialization towards pollinator morphology. Here we explore floral tube length evolution within Tritoniopsis revoluta (Iridaceae), a species with considerable geographic variation in tube length. We ask whether tube lengths of T. revoluta populations are associated with proboscis lengths of their pollinators, whether floral divergence occurs in the presence of different pollinators, and if floral convergence occurs between distantly related populations pollinated by the same pollinator. Lastly we ask whether tube length evolution is directional. Shifts between morphologically different pollinators were always associated with shifts in floral morphology, even when populations were very closely related. Distantly related populations had similar tube lengths when they were pollinated by the same pollinator. Shifts in tube length tended to be from short to long, although reversals were not infrequent. After correcting for phylogeny, there was a strong positive, linear relationship between floral tube length and the lengths of pollinator proboscides, suggesting that plants are functionally specialized on different pollinators at different sites. However, because of the apparent lack of intrinsic constraints on the evolution of this important adaptive trait, functional specialization is unlikely to lead to canalization or range limitation.