Opuntia pailana up to 9 centimeters width. The areoles with dark color support grey-yellow glochids, with long white hairs of trichome. The areols support also thorns 2 to 3 centimeters long with white or light grey color, with some darker strips. Most often, they are three, or six to eight on older plants. Opuntia pailana Opuntia pailana is a species of the genus "Opuntia" in the family Cactaceae. The name "pailana" comes from the sierra de la Paila in the state of Coahuila Mexico where it was discovered. The first description was published by Wilhelm Weingart in 1929 in the book "Monatsschrift
Opuntia engelmannii (state) to the Tamaulipan matorral in Chihuahua (state), in Mexico. In the Sonoran Desert, terminal pads face predominantly east-west, so as to maximize the absorption of solar radiation during summer rains. Although found occasionally in the Mojave Desert, it tends to be replaced by "Opuntia basilaris", which does not need the summer rain. The overall form of "Opuntia engelmannii" is generally shrubby, with dense clumps up to high, usually with no apparent trunk. The pads are green (rarely blue-green), obovate to round, about 15–30 cm long and 12–20 cm wide. The glochids are yellow initially, then brown with age. Spines