Here are some excellent pin cushion-type cactus or mamillarias for houseplants and outdoor gardens in warm areas.
Mexican pin cushion (Mamillaria magnimamma)
Native to Mexico, this clumping species is deep green. The bodies can reach nearly four inches in length. The tubercles are highly decorated with woolly hair-like growths from the areoles and between the tubercles. The curving spines have black tips. The blossoms are creamy white. Because it is so easy to grow, it is highly recommended as a houseplant.
Old lady cactus (Mamillaria hahniana)
Native to Mexico, this is one of the favorites because of the white bristles that resemble hairs. The central spines are also white with red on the tips. This deep green plant is globe-like and grows to nearly four inches in diameter, which is wider than tall. Old lady cactus produces offsets to create a cluster as it gets older.
Beginning when the plant is very young-only a few years old, this has blooms that can range in color from red to purple or reddish-violet. These reach ½ inch across and are slightly larger in length. They appear from spring into the summer.
Rose pin cushion (Mamillaria zeilmanniana)
Initially the plant is shiny green and globe-like, but at maturity it is more cylindrical. The deep green plant is covered with thin, white and brownish-red spines, which can be curving. As the plant matures, it can develop offsets. This reaches two inches in height with a matching spread.
This very floriferous plant blooms when very young. The blooms are usually white. They can be nearly an inch in diameter.
Silver cluster cactus or little candles (Mamillaria prolifera)
This deep green plant is named for the very small, cylindrical or globular bodies that appear in round clusters. These bodies are covered with white, bristle-like spines that arise from the axils between the tubercles.
This is usually around two inches in height with an almost comparable diameter. While the radial spines are white, the others are golden.
The blossoms are white or yellow with brown tinges. These open during the spring and summer months. Small in size, these are only ½ inch in diameter and length. They have a brown streak.