The leaf of Darlingtonia is unique: it is tubular, and contains a fluid that digests trapped insects. The upper part of the leaf, show here, is modified for the trapping function. The end of the leaf is hooded. There is a circular opening through which insects can fly into the hood. So why would they do so? One reason: on the two flag-like structures, there are glands that secrete sugary nectar, such as flies and other insects like to fed on. There are more nectar glands inside the hood, so an insect tends to progress right into the hood.