Cleistocactus strausii
As a houseplant, the Silver Torch cactus is an easy to take care of so long as over-watering is avoided. To naturally simulate the porous effects of the sand in its native habitat, it's important to ensure that excess water will not pool in the soil, causing the roots to become water logged.
This plant’s native habitat does not have winter, but when temperatures drop to the low twenties, it can exhibit signs of tip frost. 
The Silver Torch cactus is most susceptible to 
mealybugs 
and spider mite.
Ferocactus wislizeni
In adulthood, fishhook barrel cacti generally lean southward, toward the sun, earning them the nickname "compass barrel cactus." One theory about why this happens is, the afternoon sun is so intense it slows the growth on the exposed side, causing the plant to grow unevenly. Older barrels can lean so far they uproot themselves and fall over, especially after heavy rains when the soil is loose. Its life cycle is 50–100 years.