76035 P. leucium Rather lush plant up to 4 ft. high. Some area as 76034. 76036 P. argentatum Rocamontes, Zacatecas 8.5 km. south of Saltillo just inside Zacatecas. Shrub abundant on well drained hillside, up to 4 ft. high, some introgression but many plants showing no evidence of introgression even tho mairula is all around. This is the area where Ing. Hector Gomez has his experimental plots on guayule harvesting. Aug 30, 1976 76037 Nericyenia linearifolia (Wats.) Greene var. mexicana Bacon same locality as 76036. - annual, pretty well dried up. n = 10