Locality: canyon & adjacent slopes; bridge to 3 km east, 45 km E of Agua Prieta on MEX 2; Chihuahuan desertscrub on limestone/ quartzite substrates with cottonwood-willow riparian gallery in canyon bottom; 31°18â53âN 109°08â23âW, ~1250m elev (31.310000, -109.140000)