Opuntia tomentosa is endemic to Mexico, where it is widespread in the Mexico Federal District and the states of Aguascalientes, Guanajuato, Guerrero, Hidalgo, MĂ©xico State, Michoacán, Morelos, Nuevo LeĂłn, Oaxaca, Puebla, QuerĂ©taro, San Luis PotosĂ, Tamaulipas, Tlaxcala, and Veracruz (and Jalisco?) and Guatemala. It is adventive in Australia, South Africa and elsewhere as a minor rangeland pest.Altitude range: It grows from 1,090 to 2,600 metres above sea level.Habitat and Ecology: This species is mostly found in sub-tropical, semi-arid and warmer temperate environments. In Mexico it inhabits Quercus forests, xerophyllous scrub and grasslands in a volcanic area on shallow soils, and tolerates disturbance. Climate is semi-arid and modified by altitude, however water availability is highly restricted due to a great percolation caused by the rock structure and to low water retention from the shallow accumulated soil and also a daily wide temperature fluctuation could occur (as wide as ~ 34°C).