Asarina filipes

This is a low twining plant easily overlooked were it not for the flowers. This plant is also often listed in the genus Antirrhinum. Asarina seems to be the more recent placement, and is appealing from the point of view of basic morphology, given this plant's similarity to Asarina antirrhiniflora.

A flower at Organ Pipe Cactus National Monument, 2/25/05.