Along with the dandelion, we in the eastern U.S. have polkberry plants (they are very common here as they are spread wide by the birds) and polk salad was popular among the poor, rural population a century ago. It had to be twice boiled (maybe more) to be safe, though.

I can't understand how contestants on the Naked and Afraid show can't find leaves or roots to eat. 21 days is not that long. I am also curious how they use worms for fishing and trapping, but they can't find insects to eat.