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.

Fig 113. [Red Clover. Trifolium pratense] L.

Red Clover. Trifolium pratense L. Seeds usually dull, pure light yellow to purple, flattened, ovoid, having the seed scar near the middle of one edge or below the middle, half anatropous, a slight depression on each side from the scar toward the broad end, the short edge thinner than the long edge, 1.5–1.8 mm. long by 1.×1.4 mm. wide. Very common. Introduced from Europe.

Mammoth Clover is a variety or race or red clover, the seeds of which are indistinguishable from the seeds of red clover. As a rule they are darker in color and rather smaller. Red clover and mammoth clover are usually much mixed.

Fig 114.[Low Hop-clover. Trifolium procumbens] L.

Low Hop-clover. Trifolium procumbens L. A low, yellow-flowered annual, often becoming a tumble-weed at maturity. Seeds plump, shining, straw-colored to light brown, broad oval, very slightly flattened, 1 mm. long, three-fourths anatropous, i. e., the scar is a very little distance from one end of the seed. A little way back of the scar on each side is a light-colored depression. Rather rapidly spreading. From Europe.