As Craig figured out, our mystery seeds from last week were from plants of the genus Solanum.
The plants have silvery green leaves...
and purple flowers.
Several nightshades in the genus Solanum grow in Arizona.
Another common member of the same family (Solanaceae) is the blue potato bush vine, a landscape plant that is buzz pollinated by bees. It used to be called Solanum rantonnetii, but has recently been moved to the genus Lycianthes. As you can see, the purple flowers are similar in structure to the nightshades above.
Doe silverleaf nightshade grow where you live? What about other members of the genus Solanum?