Which of the following genuses is native to United States and Mexico, Leucophyllum or Eryngium?
Leucophyllum: Leucophyllum (barometer bush or barometerbush) is a genus of evergreen shrubs in the figwort family, Scrophulariaceae, native to the southwestern United States and Mexico. Eryngium:  The genus has a cosmopolitan distribution, with the center of diversity in South America.
Leucophyllum