The Deserts down in Mexico

Abstract

“Wide and weary desert areas of mountain and plain.” (C.G. Pringle) In late July 2017, twenty cactophiles on the CSSA Pre-Convention tour traveled through northeastern Mexico in a loop west from Monterrey and back again. The group passed through the states of Coahuila and Nuevo León traversing the northern foothills of the Sierra Madre Oriental and the southern portion of the Chihuahuan Desert Region (CDR), a high plateau trapped in the rain shadow between the two cordilleras of Mexico (Fig. 1). This geographic isolation, the land pattern of basin and range, and the harsh soils and “floods of white sunlight” (Pringle) have favored the survival of the high diversity and high endemism in the Cactaceae of the region — (CDR holds 59% of all cactus species in Mexico). This meant there would definitely be iconic cactus for the group to see. Or at least try to see, for unlike the columnar cactus forests of warmer southern states, Hidalgo, Puebla and Oaxaca, the cactus of the CDR, (leaving aside Echinocactus platyacanthus and Ferocactus pilosus), are small and globose, some miniature, at times cryptic, at times narrowly distributed, often sheltering inconspicuously in the warmth of a gypsum crust, a basal rosette, or a limestone ledge (Figs. 2 & 3).