Opuntia echios Bay on Santa Cruz, "Opuntia echios" var. "inermis" on the Sierra Negra Volcano on Isabela and "Opuntia echios" var. "zacana" on North Seymour. Opuntia echios Opuntia echios is a species of plant in the Cactaceae family. It is endemic to the Galápagos Islands (Ecuador) and is commonly known as the Galápagos prickly pear, but there are five other species of prickly pears that also are endemic to the archipelago ("O. galapageia", "O. helleri", "O. insularis", "O. megasperma" and "O. saxicola"). There are five varieties of "Opuntia echios", each with a different appearance and distribution: "Opuntia echios" var. "echios" on the
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