Xerophyte

Description

Pterocactus araucanusSN|30778]]SN|30778]] is a geophyte cactus with a massive underground tap-root, and several deciduous stems with spines not covering them. This plant grows in sandy soil, with almost the entire plant underground. P. araucanus is one of the best-loved species in cultivation because it is not supposed to have glochids.

Roots

This species forms thick rootstocks constricted at the collar that help to survive the dry periods.

Glochids

Usually absent, but in some forms a few glochids may appear after the juvenile stage.

Blooming Season

Summer.

Spines

About 8, pectinate, yellowish with darker tips, to 3 mm long. Sometime a long and powerful central spine is produced in the centre of developed segments.Flowers* Diurnal reddish brown, opaque, 3-4 cm in diameter. The flowers are terminal produced from the apex of new growth. Stamens and style are yellow.

Stem

Segments globose to pear shaped, arising one above the other, grey-brown, 3-4 cm long (up to 8 cm in cultivation), 1-1.5 cm in diameter. The whole plant up to 10 cm wide.

Fruits

Borne apically, dry at maturity, globose, 2 cm in diameter, transversely dehiscent at apex.

Areoles

Elliptical, 2 mm long and 1 mm wide.