Stinging Nettle
Full List
Cnidosculus stimulosus - Slide #12

Not a very good picture, but a plant you should learn to recognize. Stout bristles cover the stem and leaves of this plant and should NOT be touched. They will produce an immediate and painful stinging reaction - I know from personal experience. Belongs to the same family as Christmas Poinsettias. Much more common in south Alabama on the coastal plain - rare in the northern part of the state.