Flower:

1 or 2 nearly stalkless pea-shaped flowers in the upper leaf axils. Flowers are ¾ to 1¼ inch long, pink to purple, the upper petal (standard) is broad, flaring up and notched in the center, the two lateral wings below it are oval shaped and often darker colored than the standard; they flank and obscure the lower keel underneath. The calyx holding the flower is usually minutely hairy with prong-like teeth about as long as the tube (see fruit photo below).

Leaves and stems:

Leaves are compound in 4 to 8 pairs with a branched tendril at the tip to clasp surrounding vegetation for support. Leaflets are oval elliptic to nearly linear, ¾ to 1¼ inches long, 1/6 to 1/3 inch wide, sparsely hairy on the underside, often flattened or indented at the tip, with a small spine-like projection. A pair of leafy appendages (stipules) at the leaf joint are small and somewhat variable, with 2 or more sharp teeth, often with a small dark gland spot underneath. The slender stems are viney, branched and ascending or climbing and hairy to varying degrees, sometimes minutely so. 

Fruit:

Fruit is a flat pea pod up to 2 inches long, producing 4 to 12 round beans. Pods ripen to light brown.

Notes:

Considered a crop and garden weed, Common Vetch has also been used as a green manure crop and for forage. It escaped cultivation. Ants seem to have a particular fondness for this plant, as it is common to find them nectaring at the gland on the stipule. There are 2 subspecies, subsp. sativa (described above) and subsp. nigra (formerly called Vicia angustifolia), both of which may be found in Minnesota. Subsp. nigra flowers are usually less than ¾-inch, its calyx teeth are shorter than the tube, pods ripen to black, and is usually hairless.