Xerophyte

Habit

It is usually solitary unless damaged.

Flowers

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

Forma Aurea

The schizochromic form (Astrophytum asteriasSN|1464]]SN|1464]] f. aurea) has pale yellow stems due to the absence (or reduced production) of chlorophyll pigments

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

Cream-yellow to bright golden yellow, 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, dotted with numerous minuscule tufts of bright white wool (hairy scales). Cultivated plants possess sometimes very dense and big hairy scales. The short white wool on surface, said to substitute for lack of shade from spines. There are also completely flake free specimens.

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.