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 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