Sources

http://www.britannica.com/EBchecked/topic/87832/cactus

http://www.desertusa.com/cactus/the-cactus.html

http://members.tripod.com/~Pharm_D/cachistory.html

http://www.erowid.org/plants/cacti/cacti_guide/cacti_guide12.shtml

http://terraria.gamepedia.com/Cactus


The book “Cactaceous plants: their history and culture.” By Castle, Lewis.
As a pdf file http://ia600404.us.archive.org/0/items/cu31924002813529/cu31924002813529.pdf