Coefficient of Conservatism:
Coefficient of Wetness:
B. S. Walters
Roadsides, fields, railroads, disturbed areas in forests, shores, disturbed places generally. Of similar status to M. albus, but only more recently becoming abundant, even though first collected in 1876 (in Shiawassee Co.).
This species begins to bloom several days earlier than M. albus. The only consistently reliable way to distinguish the two is by flower color. Some yellow is usually detectable even in old dry corollas of M. officinalis. The racemes in M. albus at peak of flowering are often much longer (8–15 times as long as wide) than in M. officinalis, where they are rarely more than 6 times as long as wide. In M. albus, the standard often distinctly exceeds the wings, while in M. officinalis it is usually about the same length, but there are many exceptions. The leaflets of M. officinalis tend to be broader, usually no more than about twice as long as broad, while in M. albus they are often narrower (ca. 2.5–3.5 times as long as broad).