Bumblebee Pollination of Melampyrum ciliare (Scrophulariaceae)

Melampyrum ciliare has tubular flowers predominantly visited by Bombus diversus. Floral structure (including the positions of anthers and stigma) and structure of the distal part of the corolla indicate cross‐pollination by bumblebees. In M. ciliare , young flowers with white spots on the labium, which disappeared with flower aging, produced larger amounts of nectar than older ones without spots. Bumblebees visited flowers with white spots significantly more frequently than would be expected if they chose flowers randomly. These findings and the high seed production of open‐pollinated flowers suggest effective pollination of M. ciliare by bumblebees.