Mammillaria spinosissima, also known as spiny pincushion cactus, is a species of flowering plant in the cactus family Cactaceae, endemic to the central Mexican states of Guerrero and Morelos where they grow at elevations of 1,600 to 1,900 meters.
Mammillaria is common cacti at shows and garden centers both for their appearance and their desirable traits in cultivation. This huge genus of plants contains at least 275 species of highly variable forms, and thus are highly prized among collectors. They are also known as powder puff cacti. Although this genus does include some plants that are very difficult to maintain, the most common ones are usually very easy and will stay small enough and grow slow enough to provide years of enjoyment. When they do flower, many species have a "crown" of flowers that surround the top of the plant like a wreath.