=Black Medick. Nonesuch.= _Medicago lupulina_ L. Flowers light yellow; pods black, oval, much flattened, spirally coiled, causing the two extremities to nearly meet; 2-2.8 mm. long; seeds smooth, dull yellow to green, oval, flattened, kidney-shaped, with a tubercle near the middle of the concave edge or like the figure, 1.5-1.8 mm. long. Introduced from Europe and becoming frequent in grass land. Its worst feature is to supply seeds that may be mistaken for and mixed with seeds of alfalfa and red clover. The seeds differ from those of alfalfa in being more commonly egg-shaped than kidney-shaped in outline. The scar is nearer the small extremity in these seeds than in those of alfalfa. For pasture this is less valuable than white clover. [Illustration: Fig. 109.] =Alfalfa. Lucerne.= _Medicago sativa_ L. Seeds varying much in shape and size owing to their crowding in the pod when young, yellowish green to light brown. The cuts give a good idea of the variety of shapes; surface dull or somewhat glossy, often kidney shaped, with the scar in a depression near the middle, the tips may be truncate or acute or rounded, 2-2.5 mm. long in cross-section, oval; when viewed from one edge it is seen to be bent or warped in various ways, half anatropous, often seen with a slight depression extending along one edge from the scar to one end, larger seeds more often flattened than are the shorter. A prominent forage plant, the seeds of which are often adulterated. Native of Europe. [Illustration: Fig. 110.] =White Sweet Clover.= _Melilotus alba Desv._ Flowers white; pods straw-color to brown, coarsely and irregularly reticulate-ridged or wrinkled; seeds smooth, dull, yellowish or greenish, more strictly elliptical-oblong in outline than those of red clover and alfalfa, bearing the broad, shallow notch near one extremity; 2-2.2 mm. long. Introduced from Europe. Seeds used to adulterate those of alfalfa. [Illustration: Fig. 111.] =Alsike Clover.= _Trifolium hybridum_ L. Seeds dull yellowish green to very dark green, some of them mottled, lighter about the seed scar, flattened, one of the rounded edges thicker than the other, and between the two a slight groove on each side; seed rounded at one end, the other truncate with the seed scar in the middle of the truncate end. Some seeds are half anatropous, resembling in shape those of red clover; 1.3-1.2 mm. in diameter. When compared with white clover, these seeds are larger and thicker. Introduced from Europe. [Illustration: Fig. 112.] =Crimson Clover. Scarlet Clover.= _Trifolium incarnatum_ L. Seed smooth, shining when not old, color light yellow to reddish yellow or brown, oval, scar about one-third the distance from the narrow end, three-fourths anatropous, 2-2.5 mm. long, very slightly compressed. [Illustration: Fig. 113.]