13b. Hilum about 3 1/2 mm. long, flat, grayish and scurfy; seeds slightly flattened, dark brown with obscure mottling. V. americans, American vetch (not illustrated).

8b. Seeds relatively large, length 4-5 or 6 mm., up to 14 mm- in faba.

14a. Chalaza 2 1/2-3 mm. from end of hilum; hilum about 1 mm. long, 1/2 mm. wide. Seed dull, pale brownish and usually mottled with dark green, the side opposite the chalaza flattened at right angles to the hilum so that seed appears triangular in outline. V. ervilia, bitter vetch (not illustrated).

14b. Chalaza 1 mm. or less from end of hilum.

15a. Seed spherical or slightly flattened.

16a. Hilum flush with seed surface, smooth and flat, color black or reddish, length about 2 mm., width 1 mm., seeds black or obscurely mottled. V. villosa, hairy vetch (figure M). V. villosa var. glabrescens, smooth vetch.

16b. Hilum depressed at the margins.

17a. Hilum linear-oval, flat, the surface slightly granular and scurfy with a light-colored strip along the groove down the center, length about 2 mm., width 3/4 mm. or less; seed dull black or obscurely mottled. V. dasycarpa, woollypod vetch (figure N).

17b. Hilum linear-ovate, raised down the middle along the groove, length 2-2 1/2 mm., width 1/2 mm.; seed color variable, commonly reddish brown and obscurely mottled. A variable species.

V. saliva, common vetch (figure L).

15b. Seed broadly oblong or oval, thick, flattened, reddish brown, length 13-14 mm., width 8-9 mm., hilum lies along the narrower end, length 5-6 mm., width 1 1 1/2 mm.

V. faba, horsebean (not illustrated).