Maihuenia poeppigii is a shrubby, much branched, prostrate, succulent plant originally described as an Opuntia, but there are no glochids, and differences in seed and other microscopic features. It is hardy cactus that forms large mats of cylindrical stems with small, succulent leaves and white spines, often consisting of hundreds of individual segments. It is small in size, and can reach 10-15(-20) cm in height, but it can grow up to 2 meter in diameter. This is a common adaptation to cold, windy alpine habitats. The flowers are very showy, large, satiny and lemon-yellow in colour.