Xerophyte

Habit

It is usually solitary unless damaged.

Forma Rubra

The red schizochromic form (Astrophytum asterias var. nudum f. rubraSN|1464]]SN|26115]]) has bright orange-red stems due to the absence (or reduced production) of chlorophyll pigments

Flowers

Apical, diurnal, radial, 3-5 cm long, 5-7(-9) cm in diameter opening widely, yellow with orange/red throats.

Blooming Season

Spring to summer and each flower lasts for one or two days only.

Spines

Not any.

Ribs

The stem is typically divided by very narrow but distinct vertical grooves into 8 broad ribs. The ribs are very low, almost flat on top, forming triangular sections with no cross-grooves.

Stem

bright orange to dark red, much depressed, disc-shaped to low dome-shaped (Only in cultivation plants may have a spherical till columnar shape, mature plants 2-7 cm tall, 5-16 cm broad, smooth completely flake free (without the minuscule tufts of bright white hairy scales).

Areoles

Round, prominent, 3-12 mm in diameters, forming a line up to the centre of each rib, felted to hairy, white till straw-coloured, then grey. Normally 3 to 10 mm apart.