Ariocarpus retusus
 Ariocarpus retusus is a species of cactus from the genus Ariocarpus found mainly in Mexico. It is one of the largest and fastest growing species of the genus. Despite its slow growth often taking 10 years to reach flowering age the retusus is a desirable cactus for cultivation having attractive flowers and an interesting form. It is also one of the easiest cacti to grow from the genus.