– Astrophytum (2017)

By Eric Driskill (June 2017)

During the first half of the 19th century, in 1839, Charles Lemaire described Astrophytum. The name Astrophytum is derived from the Greek aster, “star”; and phyton, “plant.” Lemaire described the genus from a specimen of A. myriostigma from northern Mexico.

Britton and Rose listed four Astrophytum species in the second edition of The Cactaceae in 1937. Sixty-four years later, Edward Anderson’s The Cactus Family also listed the same four species. In 2006, in The New Cactus Lexicon, David Hunt listed six species. The two additional species were A. caput-medusae and A. caohuilense. Depending on whether you are a clumper or a splitter, you could own hundreds of species with no two plants looking exactly alike.

With one exception, astrophytums are solitary, globose to columnar and green. One feature that really sets this genus apart from most others is the plants’ often-dense covering of fine, white tufts of trichomes. The presence of these trichomes may aid in the collection of water or possibly helps protect the plants from the sun. Whatever its purpose, this feature certainly adds to the popularity of the genus.

Astrophytums are found from northern Mexico to southern Texas. The plants have three to 10 ribs. Spines may be absent or present and variable. Astrophytums generally flower in the summer over a period of several weeks. All species have similar flowers, which are borne at the stem tips and open during the day. The blooms are large, funnel-shaped and yellow or yellow with red throats.

The exception to the above description is A. caput-medusae. This oddity is from Nuevo Leon and has elongate, short-lived tubercles from tuberous rootstock. This plant demonstrates geophytism coupled with the elongation of the tubercles to serve as succulent “leaves.” This is paralleled in a less striking way in ariocarpus (A. agavoides) and by Leuchtenbergia principis.

Whether you prefer the more globular style of A. asterias or more of the columnar shapes – after many years of growth – of A. capricorne, A. coahuilense, A. myriostigma and A. ornatum, these plants are impressive. You can obtain smaller plants of most species for very reasonable prices. You can also spend a small fortune for some of the more bizarre plants bred for their unique shapes, textures and patterns of trichomes. Beautiful examples of most of these species can also be found as variegated plants, with many of these at reasonable prices.

Certainly the most rare astrophytum in cultivation and available for purchase is A. caput-medusae. When this plant is available, you will most often find it grafted.

With all species, you should consider a well-draining soil mixture. Careful and frugal feeding, and years of patience will reward you with hard-grown, compact plants. No cactus collection is complete without one or two representative astrophytums.