notes Two flowers of Aristolochia watsonii are visible here in the axils of the upper leaves. This is a fascinating desert-adapted member of the genus Aristolochia. It's a low-growing vine with narrowly saggitate leaves that are dark purple-brown above, bright-green underneath, and full of phytotoxins that are consumed and sequestered by the pipevine swallowtail butterfly (Battus philenor)...this being its host plant in the Sonoran desert portion of its range.
The strange flowers have a musty odor and resemble a mouse's ear, which attracts the pollinators...blood-sucking midges of the family Ceratonpogonidae...which are fooled into entering the flowers in search of a meal and are then trapped overnight, become covered with pollen, and are released the next morning.
Learn more about pollination, phytotoxins, and the pipevine butterfly at this summary web page from the Arizona-Sonora Desert Museum. Also highly recommend is the wonderful & more detailed article by Crosswhite & Crosswhite(1984) here.
Detailed botanical information for this species can be found on this SEINet web page.
