  
 
Astrophytum is a genus of six species, native to the Chihuahuan desert and occurring in north and central Mexico and southern Texas in the USA. Of these six species five, namely Astrophytum asterias, Astrophytum capricorne, Astrophytum coahuilense, Astrophytum myriostigma and Astrophytum ornatum are globose to short cylindrical cacti while the fifth, Astrophytum caput-medusae is a sprawling octopus-like plant. The first five species mentioned were discovered between the years 1828 and 1845. Astrophytum asterias, Astrophytum coahuilense and Astrophytum myriostigma are spineless while Astrophytum capricorne and Astrophytum ornatum have prominent spines. All five feature a star-shaped appearance when viewed from above hence the genus name Astrophytum, which means star plant.   
  Despite the noticeable differences, all 5 species including Astrophytum caput-madusae feature a sort of flocking of white trichomes (or bumps) on the epidermis. The four original Astrophytum members have been extremely popular in cultivation and numerous exotic hybrids have been created that emphasise various features such as amount of flocking, number of ribs, lack of spines, etc. These plants are adapted to the varying extremes of the desert, from high daytime temperatures to frosty nights, and they tolerate dry conditions very well, like other cacti.
 Gardeners should be careful to avoid over-watering their Astrophytum cacti in the garden. For succulent gardens, rockeries, and other water-wise gardens, Astrophytums can be an excellent choice. Outdoor gardening in containers and pots is also possible. They are summer growers requiring full to part sun. Provide them with lots of water in summer but only moderate water in spring and autumn, and no water in winter as they are prone to rot. They are frost tolerant to -10°C.
A very perfect disguise is found with Astrophytum myriostigma which the Frenchman Lemaire described in 1839. With its five-ribbed thick body, covered with white wool spots and without spines you can find it hardly at its locations between the lime rocks of San Luis Potosi and Tamaulipas. The species name “myriostigma” means thousand dots. Many cactus collectors discovered and described later varieties where plants are without wooly dots (nudes), plants with only four ribs and old Astrophytum myriostigmas with seven, eight or more ribs. However, they all have pure yellow flowers like Astrophytum ornatum.
  
 
  
|
