Here in the land of ten thousand taxes we have what
the old timers called burn nettles.. I do not know the
real name of the plant, but nasty as heck. We used railroad
gloves to pull them out, cause if you touched them the
burning,swelling and itching was horrible. They also blend
in very well with other plants and weeds.
Pictures at this site. You might be able to identify your nettle. Nettles
We have the nettles you speak of here, too (another reason to wear long pants year round). Someone told me they have medicinal value, but I do not recall what it is.