Cleistocactus strausii

Silver torch cactus
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Core eudicots
Order:	Caryophyllales
Family:	Cactaceae
Genus:	Cleistocactus
Species:	C. strausii
Binomial name
Cleistocactus strausii

Silver torch or Wooly torch cactus (Cleistocactus strausii) is a succulent of family Cactaceae. It is native to high mountain regions of Bolivia and Argentina.

Its slender, erect, grey-green columns can reach a height of 3 m (10 ft), but are only about 6 cm (2.5 in) across. The columns are formed from around 25 ribs and are densely covered with areoles, supporting four yellow-brown spines up to 4 cm (2 in) long and 20 shorter white radials.

The cactus prefers free draining soils, strong sunlight, but not high temperatures — in fact it can withstand hard frosts down to -10°C. In its natural habitat it receives plenty of water during the summer, but almost none over the winter. In cultivation, watering too much in winter often leads to root rot.

Older cactuses, over 45 cm (18 in) tall, produce deep red, burgundy, flowers in late summer. The 6 cm (3 in) long cylindrical flowers protrude horizontally from the columns. In common with other cacti in the genus Cleistocactus, the flowers hardly open, with only the style and stamens protruding. Cultivated plants often flower freely.

When mature, the silver torch cactus produces deep red flowers extending horizontally from the main columns.

References

• desert-tropicals.com
• University of Connecticut Ecology department
• Bihrmann's caudiciforms

External links

• close up picture of flowers