Black medic (Medicago lupulina), introduced from Eastern Europe and Asia, is found throughout most of North America. Originally planted as fodder, this annual (or short-lived perennial) now invades lawns, gardens, roadsides, waste areas and disturbed sites. Black medic has value as forage and a cover crop and, like other legumes, fixes nitrogen in the soil. However, when black medic overruns cultivated land it is often considered a noxious weed.
A low, trailing plant, black medic has branching stems that radiate out from a taproot. Its compound leaves have three oval leaflets with fine toothed margins and prominent veins. The central leaflet is on a short stalk. The leaf stalk has a stipule (appendage at the base of the stalk). The small, bright yellow, pea-like flowers are borne in dense, rounded clusters. Black medic fruits are thick-walled, kidney shaped pods containing one seed. The seeds are green, turning black as they mature. The plant is covered with fine hairs.
Honeybees visit black medic flowers. Occasionally fields are planted to black medic for honey production. A flour can be made from dried black medic seeds and the greens of this plant are used as a potherb. There are reports that black medic contains trypsin inhibitors, so I never was tempted to ingest it in any form. Modern herbalists ascribe antibacterial properties to a water extract of black medic.
Another common name for black medic is nonesuch. Medick is an alternate spelling for medic. This name has nothing to do with medicine, but rather refers to “medike”, an ancient plant from Persia. Alfalfa is another member of the Medicago genus.
The black medic plants in the photographs were growing along Ash Creek (Lassen County CA).