The range of Lophophora Williams II includes both the Tamaulipan thornscrub and the Chihuahuan desert (Anderson 1996), while Astrophytum asterias has a much more restricted range in the Tamaulipan thornscrub only (Damude and Poole 1995; Martinez Avalos 2002; Sanchez-Mejorada et al.1986). The ranges of the two species overlap in the Lower Rio Grande Valley of southern Texas, USA, and in northern Tamaulipas and Nuevo Leon, Mexico.

Distribution of peyote (dashed lines) and star cactus (shaded area) in southern Texas and northern Mexico.
Adapted from Anderson (1996), with star cactus locality information from Martinez Avalos (pers. com.)

Area of Tamaulipan thornscrub, habitat for peyote and star cactus.

Within the Tamaulipan thornscrub, star cactus grows in gravelly clays or loams, on gentle slopes in sparsely vegetated openings between shrub thickets within mesquite-blackbrush thorn shrublands. Associates of both Astrophytum and Lophophora in Texas include the shrubs Prosopis glandulosa, Castela erecta, Acacia rigidula, Ziziphus obtusifolia, Koeberlinia spinosa, Forestiera angustifolia, Guaiacum angustifolium, Karwinskia humboldtiana, Varilla texana; grasses (Bouteloua trifida, Monanthochloe littoralis, Aristida spp., Hilaria belangeri), and numerous cacti (Opuntia leptocaulis, Echinocactus texensis, Mammillaria heyderi) (Damude and Poole 1990; Texas Parks and Wildlife Department and The Nature Conservancy of Texas unpublished field data).

Star cactus and peyote growing under canopy of Krameria ramosissima.

With a young example of the endemic Coryphantha pottsiana [syn. C. robertii] in background.

Castela erecta and Opuntia leptocaulis have been documented as important nurse shrubs for star cactus (Martinez Avalos, 2002).

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