The Astrophytum ornatum is the largest and easiest to grow and also the fastest of the Astrophytums. Spherical when young to columnar when mature, some specimen develop nice twists with age. Ribs have characteristic cross bands of wooly scales.
 

Desription: The stem is solitary, globose when young , cylindric with age, up to 1,2m or more high, 15-30 cm across, dark green with sparse white or yellow wooly flakes in bands. It has 5 to 8 (generally 8)  straight or frequently spiraling, strongly compressed, more or less sinuate, crenate ribs.  Areoles at first yellowish-white felted, later grabrescent, with 5-10 stout, 2-4 cm long straight radial spines laterally compressed, amber yellow, later brown and finally grey, and usually 1 rather larger central spine.

Origin: Astrophytum ornatum is the southern genus of Astrophytum. The habitats are at Hidalgo, Queretaro and Guanajuato in Mexico.

Conservation status: Listed in CITES appendix 2.

Habitat:  grows in wild canyons and limestone cliffs.
 

The Astrophytum ornatum blooms in summer. The flowers (6-8 cm wide) are pale yellow with bright silken sheen and scented.
 

Coltivation: This cactus is pretty cold hardy and can survive to -10° C (if kept dry).  It needs to be at least 15 cm tall to bloom . This might take no less than seven years or more depending on the length of the growing period in the local climatic conditions.

Photo of conspecific taxa, varieties, forms and cultivars of Astrophytum asterias.

• Astrophytum ornatum
• Astrophytum ornatum var mirbelii
• Astrophytum ornatum var. virens
• Astrophytum ornatum forma cristata