Wild senna flower heads can be a foot long. It makes an excellent garden plant. Senna was used to treat a wide variety of ailments. You'll notice that senna has anthers of two sizes. This apparently helps sort the bees, insuring just the right size for pollination. Maybe this should have been called Goldilocks. That might be better than the rather vague wild senna. There are many species of senna that grow wild across the country, particularly in the south.