This Cactus information is referring to the prickly pear cactus. They grow in Wisconsin and they grow by the billions of pounds here in Texas.
Interesting info.
http://www.livestrong.com/article/115063-nopal-cactus-health-benefits/
https://www.drugs.com/npp/prickly-pear.html
http://www.herbwisdom.com/herb-prickly-pear-cactus.html
Eating
http://healthyeating.sfgate.com/eat-nopalitos-raw-7922.html
http://www.wikihow.com/Eat-Prickly-Pear-Cactus