common vetch, Vicia sativa

Common vetch seeds have been found at Old World archeological sites as old as the Neolithic Era. These days it is mostly appreciated for its nitrogen fixing ability, and is used as green manure. It's a sprawling annual with stems up to a couple yards long. These flowers approach a half inch. This is subspecies nigra, which occurs in all states and provinces except UT, AB, LB, NF, NT, NU, SK, and YT, and it is on SPM. Bartow Co GA, 1/29/13. Bean family, Fabaceae.