Datura quercifolia  Oakleaf Datura
ANNUAL.  Leaves distinctly and irregularly lobed (not just wavy or scalloped).  Flowers white with white throats, edged with purple, very small for a Datura (about 2 cm in diameter at the top).  Seedpods egg-shaped, with a few very stout spines.  Blooms in midsummer.  Flowers open in the morning and close after noon.  On bare disturbed ground, roadsides, etc.
FAMILY:  Solanaceae (Nightshade or Tomato Family)