49 species: see species list

Cleistocactus is a genus of columnar cacti from Peru, Uruguay, Bolivia and Argentina. The name comes from the Greek kleistos meaning closed because the flowers hardly open.

The stems are tall and mostly slender and often many branched with numerous ribs with closely set areoles and spines. The flowers are tubular and the tips hardly open with only the style and stamens usually protruding.

Reference

• Innes C, Wall B (1995). Cacti' Succulents and Bromaliads. Cassell & The Royal Horticultural Society.
• The species list is referenced from http://www.cactiguide.com/ which is in turn referenced from several books which are listed on that site. The principal book listed here is The Cactus Family by Edward F. Anderson.

Species List

49 species including:
Cleistocactus baumannii
Cleistocactus candelilla
Cleistocactus dependens
Cleistocactus fieldianus
Cleistocactus hildegardiae
Cleistocactus hyalacanthus
Cleistocactus icosagonus
Cleistocactus parapetiensis
Cleistocactus reae
Cleistocactus samaipatanus
Cleistocactus sepium
Cleistocactus serpens
Cleistocactus sextonianus
Cleistocactus smaragdiflorus
Cleistocactus strausii
Cleistocactus tarijensis
Cleistocactus tominensis
Cleistocactus winteri