Underwatering
Please go to our Glossary link at the bottom of the page for explanations of scientific terms
Identification
Yes, cacti can survive for long periods without water, but if you want them to grow and flower, and to look better than this poor specimen, you'll need to water.
Having said that, it's better to underwater than overwater if you're not sure.
Prevention
Water every 1-2 weeks in summer
