Puna subterranea
(Syn: Opuntia subterranea)

Flower up to 3 cm in diameter range from brown to
deep rose red to a pale yellowish rose and rare, but possible with almost white.
 

Etymology: The genus  name “Puna” derives from the indigenous word "Puna" that indicate the western region up to 4500 m that extends from the Peru, going throughout Bolivia to the Argentinean North. Delimited  at west by a costal chain of high volcanic picks and by the Cordillera mountainous chain to the east. The Argentinean Puna is the natural continuation of the Bolivian highland.
 

Morphology (Identifying Characteristics): Small plant geophytic opuntioid cacti with very tuberous root which in remains half buried in habitat, showing approximately 1 cm. from the ground. Plants have usually few segments (up to 6). But at the northern localities this species can grow with dozends of segments. This species is very variable and there are many forms of Puna subterranea. It looks like a small Tephrocactus , but the bloom, fruit and the seeds clearly show its autonomous nature.
Stem: Grayish-green up to 6 cm wide and the same high (but usually less around 15-18 mm in diameter).
Roots: This plant has deep tuberous roots with only 1 to 3 cm growing above ground level.
Spines: Up to 10.
Glochids: Few or none near the base.
Leaves: The leaves on Maihueniopsis's are very small and fall off early.
Flowers: The blossoms up to 3 cm. long have a larger diameter than the segments is one of the reasons why P. subterranea sometimes is named 'Rebutia of the Opuntias'. At North of Argentina the colour of the blossoms is rather variable; each specimen seem to show a different colour. The flower colour ranges from brown to deep rose red to a pale yellowish rose and rare, but possible with almost white.
Blooming: time The flowering is diurnal and takes place during the summer.

Growing tips: This species resists cold well if it is dry and 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.. This mountain cactus - because of the elongated fat taproot - necessitate deep pots and a well drained mineral potting mix. They are susceptible to overwatering,  but need enough water during vegetation. Requires full sun. Specimens in culture, in special grafted ones, presents a bigger amount of glochids than the ones growing in their habitat. Need a sufficient amount of air.

Propagation:  Usually propagated by cuttings and grafting . Grafted plants in culture are most common  and sprout strongly. But it is also feasible to root them but they grow much slower on their own roots and takes various years prior to they bloom.

Conservation status:  Listed in CITES Appendix II
 

Habitat: Grows not on mountain slopes but in the Punas, the plateaus of the the high Andes.

Synonyms:  

• Maihuenopsis subterranea (R. E. Fries) E. F. Anderson 1999
• Opuntia subterranea R. E. Fries 1905
• Pseudotephrocactus subterraneus (R. E. Fries) Kreuzinger 1935
• Tephrocactus subterraneus (R. E. Fries) Backeberg 1935
• Cumulopuntia subterranea (R. E. Fries) F. Ritter 1980
• Puna variiflorus
• Tephrocactus variflorus Backeberg 1962 (non val. publ.)

Sometime Puna subterranea  produces flowers from the areoles on the hypantium of another flower. In the photo it is showed a chain of three flower originated on the flower tube of the previously produced flower.