Aporocactus flagelliformis

References

1. [1]Flowers of India — http://www.flowersofindia.net/ ↩︎A wed site of native Indian plants, plus cultivated and naturalized species. It has good quality photos and terse details on more than 3,000 species and cultivars.
2. [2]The Cactus Family — Anderson E.F. · Timber Press; Portland, Oregon · 2001 · ISBN 0-88192-498-9 ↩︎An excellent work, giving botanical descriptions of virtually all the cacti, together with their range (but not their habitats) and sometimes also a photo. it also contains a long chapter detailing the many uses of cacti and another on cultivation..
3. [3]IUCN Red List of Threatened Species — http://www.iucnredlist.org/ ↩︎A list of plants under threat and facing possible extinction, usually with brief details of the threats and information on habitat.