This widespread annual, biennial or short-lived perennial ("black medick") has been a common weed in Ky. since before 1902, when Gm noted: "used extensively for the adulteration of red clover seed, which may account for the frequent appearance of plants in cultivated ground." M. lupulina is generally much smaller, more prostrate and less long-lived than sativa, but both species develop a taproot with short spreading branches just below the soil surface, from which shoots develop. M. lupulina stems are often up to 4 dm long, but can extend up to 8-9 dm in the largest prostrate plants, especially along disturbed roadsides. Without flowers or fruits, lupulina can be confused with Trifolium dubium or T. campestre, but its stems are usually prostrate to ascending (versus decumbent to erect), 4-angled and sometimes glandular; stipules are lanceolate (versus inequilaterally ovate); leaflets are usually widest near or slightly above their middle (versus clearly above), and they have a distinctive apical point.