North of Nayos, Upper Canyon, 1.5 mi. below (north) of summit. Durango Aug 22, 1976 76012 P. argentatum Summit of mountain, 5 m South of Nayos. Variations present. No mariola seen in immediate vicinity. Limestone rubble, very dry area. No specimens taken Durango Aug. 22, 1976 76013 P. argentatum Shrubs variable as to habit and leaf cutting. Up to 3'1/2 ft. high and 3 ft in diameter. Fairly abundant over much of a hill slope. Some mariola in vicinity, .8m. below summit to the north. Shrubs similar to specimen samples of 76011. No specimens taken Aug 22, 1976