This is a strange and unmistakable crest.  Areoles connect one to each other forming characteristic horizontal lines.
 

Description: This is one of the more famous crested cacti sought after by cactus impassioned. It create  fan shaped sculpture with areoles fused to form peculiar horizontal lines,
 

Cultural Practices: It is of easy culture but slow growing. Water moderately during the summer (to much water and the beautiful fan like crest will fracture loosing it beauty, so water sparingly and permit the plant to grow slowly, any attempt to increase the speed of growth will inexorably lead to disfigure the plant with deep cracks)  Require  half shade and a well drained soil mix.

Scientific name:  Cleistocactus jujuyensis f. monstrosa cristata

Origin:  Garden origin (Nursery produced cultivar)

Conservation status: Listed in CITES appendix 2.

• Cleistocactus strausii forma mostruosa cristata
• Cleistocactus hyalacanthus "monstrous ” crested form

A crested shoot arising from the base of the common monstrous form.

Photo of conspecific taxa, varieties, forms and cultivars of  plants belonging to the Cleistocactus strausii complex.

• Cleistocactus strausii
• Cleistocactus strausii cristata
• Cleistocactus jujuyensis forma mostruosa (C. strausii f. mostruosa)
• Cleistocactus jujuyensis forma mostruosa cristata (C. strausii f. mostruosa cristata)