Distribution

This variety is native to the USA (western Texas) and Mexico (extreme northern Coahuila).

Populations around Ozona, West Texas, are invading grassland and expanding while those in Mexico are decreasing due to overgrazing and goats. The overall trend is thought to be stable

Habitat and Ecology

This variety occurs in open grassland and shrubland, sometimes associated with Juniperus pinchotii, Pinus remota, and Quercus spp.; in sandy or rocky soil on plains, on bluffs and ridges, on hillsides or along stream beds in sandy or rocky soil, commonly over limestone. The altitudinal range is 600-1,550 m a.s.l. The climate is continental, with warm summers and cold winters, drier with hotter summers in the south of its range in Mexico.

Conservation Status

Global Status

Near Threatened

Global Rationale

The distribution of this variety is poorly known; the estimated area of occupancy (96 km²) is based on only a few herbarium specimens. No specific threats have been identified for the subpopulations in the main part of its range. There is some concern about overgrazing in the Mexican areas. There is insufficient information to determine if this variety does meet the criteria for a threatened category. Consequently an assessment of Near Threatened is a conservative approach (it almost meets the criterion B2ab(iii) for listing in a threatened category). Further field work is required to establish its full distribution, population size and threats

Conservation Actions

This variety is not known from any protected area.