Nightshade

There are many different kinds of nightshade. The purple nightshade has deep purple-blue flowers.

Yellow stamens, shaped like narrow vases, have pore openings at the apex.

They are found in the higher elevations of the Sonoran Desert. The ones above were found in the San Felipe Hills. It has berries that are green to dark purple-blue when ripe. The fruit is toxic. It regrows each year from underground stems.

The silverleaf nightshade, or white horse nettle, 

has purple flowers with five yellow stamens.

The leaves are elyptic and silvery.

It is common in the Sonoran Desert where irrigation is provided, along ditchbanks, etc. Those above were found along the road between Sonoyta and Puerto Penasco, just outside El Pinacate Gran Desierto in Sonora, Mexico.