Asked by: Katrianne Lissauer, Frome
To prevent them being eaten – or more specifically, to prevent the water stored inside the fleshy cactus pads they grow on being stolen. The spines are modified leaves surrounded by irritating hairs called glochids. The fruit, called tuna, tastes sweet. Both the pads and fruit are popular in Mexico. Just don’t try eating them without wearing gloves.
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