Calycoseris wrightii  Tackstem
ANNUAL.  White flowers in April, 2-3 cm in diameter.  Nearly identical to Rafinesquia neomexicana but shorter, blooms a bit later, and has tiny transparent bead-headed glands ("tacks") on stems and calyces.  In the Empires, occasional in desert grassland, often under mesquite trees.
FAMILY:  Asteraceae (Composite or Daisy Family)