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 arenaria strongly deflexed and much shorter. Overall, plants (clumps) of cladodes may be 20–30 cm across and about 4–8 cm tall. Fruits are small, about 2.5 cm. Opuntia arenaria Opuntia arenaria was considered a variety of "O. polyacantha" by many botanists, and is still treated that way in the Flora of North America. However, "O. arenaria" is diploid and "O. polyacantha" is tetraploid. It was described by Engelmann in 1856. "Opuntia arenaria" can grow in soil that is essentially pure sand. It has rhizomes up to 1.5 m long that give rise to above ground shoots with small cladodes that are