Xerophyte

Seeds

Seed black, up to 400 per fruit.

Roots

Tuberous, 10-15cm long, up to 5-15 mm in diameter.

Flowers

Diurnal, silver-yellow, shining, outer tepals are bronze, diameter and height 2,5 (-4) cm. Stigma yellow with red stylus.

Blooming Season

May.

Spines

About 10, pectinate pink-brown that turn grey, 1-1,5mm long.

Stem

Thin, cylindrical, usually not branched, with a constant diameter ,but separated from the roots by a narrow collar. 10(-40) cm in height, diameter 1,5-2,5cm. The apex is depressed. The stems can be deciduous in the dry season, as is usual for the genus Pterocactus.

Fruits

Ovate 1,2-1, 8cm long, 0,6-1,1 cm in diameter, dark violet, longitudinally dehiscent. Covered by hairy scales.

Areoles

On small tubercles, arranged in about 30 spiral lines whit short white hairs.