This sounds like it may be Milarepa's nettle. Take a look at the pictures at
http://en.m.wikipedia.org/wiki/Urtica_dioica . Although the article says they're green I've seen them edging towards purple. Various subspecies vary greatly in stinging ability, some not stinging at all. If you identify them as Urtica dioica you might try the young leaves as cooked greens. They're quite good and higher in protein (25% dry weight) than just about any other plant. That goes a way towards explaining why someone not too picky about variety could live on a diet of primarily nettles.
Urtica roots are recognized in Europe as effective against the symptoms of prostate enlargement. You'll see warnings from US doctors on the web warning people not to use it because they're concerned it will hide the symptoms of a prostrate cancer and they won't catch it.
I took the liberty of quoting your post on bull nettles in the cookbook. If you want to do a more elaborate post I can delete that quote.