Origin and Habitat: San Juan, Argentina.
Altitude range: 1000 – 1500 metres above sea level.
Habitat and ecology: Tephrocactus halophilusSN|22334]]SN|22334]] grows, alongside the railroad from Serrezuela and on slopes with bromeliad cushions, in the saltpetre pans of the small valleys of the Sierra Pie de Palo. The bottom of the little valleys are typically occupied by unvegetated shallow salt lakes or saltpetre pans.

• Tephrocactus halophilus (Speg.) Backeb.
• Opuntia halophila Speg.

• Tephrocactus alexanderi (Britton & Rose) Backeb.
• Opuntia alexanderi Britton & Rose
• Tephrocactus alexanderi var. bruchii (Speg.) Backeb.
• Opuntia alexanderi var. bruchii (Speg.) G.D.Rowley
• Opuntia bruchii Speg.
• Tephrocactus bruchii (Speg.) Backeb.
• Tephrocactus alexanderi var. subsphaericus (Backeb.) Backeb.
• Opuntia alexanderi var. subsphaerica (Backeb.) G.D.Rowley
• Tephrocactus subsphaericus Backeb.
• Tephrocactus alexanderi subvar. brachyacanthus (Speg.) Backeb.
• Opuntia bruchii f. brachyacantha Speg.
• Tephrocactus alexanderi subvar. macranthus (Speg.) Backeb.
• Opuntia bruchii f. macracantha Speg.
• Tephrocactus halophilus (Speg.) Backeb.
• Opuntia halophila Speg.
• Tephrocactus microsphaericus Backeb.
• Tephrocactus riojanus (Hosseus) Backeb.
• Opuntia riojana Hosseus in Backeb. & F.M.Knuth

Description: Tephrocactus halophilusSN|22328]]SN|22334]], formerly Opuntia halophilaSN|22335]]SN|22335]], is a local or morphological form of Tephrocactus alexanderiSN|22328]]SN|22328]] with nore cylindrical joints, and white flowers. However the minimal differences of T. halophilus, appears to fall within the natural variation of Tephrocactus alexanderiSN|22334]]SN|22328]] and it should be fully synonymized with the latter.
Derivation of specific name: The specific name comes from the Greek “halos”, salt, and “philo”, loving. Salt-loving.

Bibliography: Major references and further lectures
1) Catálogo de las Plantas Vasculares “Tephrocactus halophilus (Speg.) Backeb.” Instituto de Botánica Darwinion - IBODA 2014 web <http://www2.darwin.edu.ar>
2) “Tephrocactus halophilus (Speg.) Backeb.” Bradleya, Volumi 14-20 page 245, The Society, 1996

Cultivation and Propagation: Tephrocactus halophilusSN|22328]]SN|22334]] (Tephrocactus alexanderiSN|22334]]SN|22328]]) is susceptible to overwatering, but need enough water during the growing season. This mountain cactus - because of the elongated fat taproot - necessitate deep pots and a well drained mineral potting mix. It prefers a full sun exposure, but should be protected from excessive heat and sun in summer.
Frost Tolerance: They tolerate light frost -5 (-10) °C.
Remarks: Need to be kept in a cool place during winter rest this is important for the flowers as well as for their health. Without this cool winter period they normally wont get many buds. Keep dry in winter to avoid rot. Need a sufficient amount of air.
Propagation: Seeds are extremely difficult to germinate. Best reproduced from rooted cuttings. Grafting is often used to speed growth rate and to create a back-up for plants in collection.