Astrophytum asterias

Astrophytum asterias is the most bizarre species of the genus, the flat ribs with scattered flakes and felted areoles resembling the skeletons of sea-urchins. In its mode of growth it is more like Ariocarpus: it remains half-hidden underground, with only tip of the crown emerging, hardly distinguished from its surroundings. The centre of its distributtion is in eastern and northern Mexico, ranging to the south of Texas. It frequents scrubland on gravel sediments with fine clay. In summer, It can become overgrown by grass. The flowera are produced throughout summer: they are yellow with a red throat. Apart from A. coahuilense, it is the least straightforward species to grow.

Astrophytum capricorne

Similarly to the closely related A. senile, even small plants are capable of the flowering; the flowers are red throated, the spines are long, soft and bent upward. Both species come from northern Mexico, growing there on limestone together with succulents of rosette form and bushes (matorrals), either exposed to the sun or in semi-shade, protected by vegetation. Several varieties of A. capricorne are distinguished, differing in the shaping of ribs, setting of spines and colour of flowers.

Astrophytum myriostigma

Bisop's cap, bishop's mitre, monk's hood
This species is prized for a look that is distinctly uncommon among cacti. Initially squat, it is the size of a small melon when about ten years old. Yes bare body may be green,blue or purple, with 4 - 8 ribs, and eventually becomes slightly columnar. The speckled look is due to innumerable white scales, which are in fact rudimentary spines. Large plants readily bear blooms that are 6 cm ( 2 1/2 in ) across and last 2 - 3 days.
H 15 cm (6 in), S 20 cm (8 in). Min 5°C (41°F).

Astrophytum ornatum

The fastest-growing and largest Astrophytum, this variable species bears many large flowers after 5 - 6 years. The ribs, usually flecked with silver and with mostly pale curving spines, spiral towards the crown.
H 1.2 m (4 ft), S 20 cm (8 in). Min 7°C (45°F).