If you’re looking for some small cacti with unusual shapes and forms, the bishop’s caps are just the thing.
Also known as the star cactus, there are several species in this group. These are native to Southwestern U.S., and Mexico. Blooming in late summer, they are sometimes spiny.
Unlike the very tropical cacti, these can tolerate cooler temperatures during the winter.
The star cactus or bishop’s caps need a coarse, well drained mix. They need to be kept pretty dry during the winter when they are resting.
If growing outdoors in warm climates, they benefit from a little partial shade during the hot afternoons. Otherwise, they need full sun.
There are several species of the bishop’s cap cactus, including the following.
Bishop’s cap (Astrophytum myriostigma)
This low growing cactus is noted for its unusual form. With an overall globular shape, the five ribs are arranged so they resemble the angles one would see on a bishop’s miter. Scattered randomly over the surface are tiny white spots. When the sun is out during the day, the large vivid yellow blooms emerge in clusters from the crown of the plant.
As young plants, these tend to be very slow growing. When mature, they reach about eight inches across. One unusual feature of the bishop’s cap is that this species is spineless.
Goat’s horn (Astrophytum carpricorne)
This plant is named for the twisted spines. Goat’s horn grows in the form of a globe with about eight ribs from which the spines emerge. It can reach almost ten inches in height. There are silvery tinges decorating the body.
The rather open, funnel-like blooms are yellow with red centers.
Monk’s hood (Astrophytum ornatum)
Also known as star cactus, this species forms a chubby globe. The eight folds or ribs are arranged spirally. As the plant becomes older, it assumes a columnar shape. This eventually grows to be about seven feet or so in height. This has tufts of stiff, sharp, tan spines. Funnel-shaped, the monk’s hood blooms are vivid yellow. Monk’s hood has lovely silver spots.
Sand dollar (Astrophytum asterias)
Also known as sea urchin cactus, this low growing, and somewhat flattened cactus has a dome shaped body with prominent indentations that resemble ribs. This has particularly attractive white spots that dot the body. In addition, there are tufted areoles, which are scattered about as well on the surface. The yellow blooms arise from the crown. These have a prominent red center. This species has large tufts of slender, tan spines.