Datura (Datura meteloides) aka jimson, thornapple, moon lily, tolguachua

The large white trumpet-shaped flowers of the datura are something of a surprise in the desert where flowers tend to be smaller and more moisture-conserving. These giant lily-like blooms are at their best in the evening and night and often close during the daylight hours. The plant grows on roadsides and in washes from 1000ft to 6000ft in elevation. Datura is a member of the nightshade family and shares the poisonous qualities that many of that family exhibit. All parts of the plant are extremely poisonous if eaten. The seed pods, which give the plant one of its common names--thornapple--are prickly and about the size of a walnut. The leaves are grayish green and heart shaped or oval. Some insects must not be bothered by the poison because often the leaves are often severely damaged by being eaten by insects. It is also reported that kangaroo rats eat the seeds.

Datura plant, photographed Hereford, AZ