Coryphantha macromeris

Distinct species.

Known from 19 counties in southern New Mexico and western and southern Texas, including the Big Bend region; approximately 65 known U.S. localities. A somewhat larger area is occupied in Mexico, extending SSE to western San Luis Potosi. May be somewhat scattered across this range, however. Not of conservation concern in either Texas or New Mexico. However, one of the two recognized varieties (C. m. var. runyonii) is of conservation concern globally as well as in Texas. This variety is subject to collecting, at least partially due to its high content of psychoactive alkaloids, as well as to occasional scouring by floods, while the typical variety appears threated by low-level collection only.

Six counties in southern New Mexico (Dona Ana, Otero, Eddy, Lea, Chaves, DeBaca), ten counties in western Texas (El Paso, Hudspeth, Culberson, Reeves, Jeff Davis, Pecos, Terrell, Presidio, Brewster, Ector), and three counties in southern Texas (Starr, Hidalgo, and Cameron) (Kartesz 2006). Extends SSE to western San Luis Potosi in Mexico, encompassing substantial areas of Chihuahua and Coahuila. Also found along a stretch of the Rio Grande river in Tamaulipas parallel to the south TX counties (Dicht and Lüthy 2005, map pg. 81).

Approximately 65 known localities in the United States (w. & s. TX and s. NM) (Benson 1982). Mexican range (including Tamaulipas, Chihuahua, Coahuila, and San Luis Potosi) somewhat larger than U.S. range (Dicht and Lüthy 2005). Species described as "uncommon but wide-ranging" (Brown 1984).

C. m. var. runyonii is subject to collecting and (often) scouring by floods. It is collected due to its high content of psychoactive alkaloids (Dicht and Lüthy 2005). C. m. var. macromeris is also a target of collection by cactus fanciers, though less so than C. m. var. runyonii.