The members of the genus Medicago have flowers that grow usually several in short to fairly elongate spikelike clusters or heads on relatively short stalks from the leaf axils. The flowers are colored yellow or bluish-purple, sometimes white. The 5 calyx teeth are equal or almost so, lanceolate and sharp-pointed, usually longer than the calyx tube, The banner of the corolla is erect, considerably longer than the wings and keel. The fruits are pods, 1- to several-seeded, strongly wrinkled, from curved to usually spirally coiled when mature, often armed with 2 rows of prickles on the exposed, keeled edges and forming a small prickly bur when mature. The plants are annual or perennial herbs with leaves that are divided into 3 leaflets. The leaflets are toothed toward the tip and have a sharp terminal tip with the midrib extending beyond the edge of the leaf edge. The middle leaflet has a longer stalk than the side leaflets. The stipules tend to be sharp-toothed. The genus contains about 50 species of Eurasia and Africa, our species are all introduced as weeds or escaped from cultivation. About one half of the species have been tested or developed in agriculture. Although alfalfa is the most common, there are several other important members of this group. The name Medicago comes from the Greek medice, apparently applied to alfalfa which the Greeks introduced from Media.
Guide to Identify Presented Species of Genus Medicago
M. lupulina Black Medic Creeping to ascending annual or biennial, found mostly on disturbed ground.
Flowers yellow, 2-3 mm long, growing in small, round clusters, 5-10 mm long.
Leaves are divided into 3 leaflets, elliptic to round, with sharp point at tips.
M. sativa Alfalfa Plant 30-100 cm tall. Introduced, mostly on disturbed ground, used for forage.
Flowers blue to whitish-yellow, 7-11 mm long, in rounded, stalked clusters.
Leaves are divided into 3 leaflets which are sharply toothed on upper halves.