8a. Flowers in heads, umbels, or short dense spikes --29.

28b. Flowers in loose racemes or panicles --42.

29a. Flowers bright-yellow; decumbent or ascending plants (spring and
summer) --30.

29b. Flowers white, cream, purple, or red; never yellow --34.

30a. Whole flower only about 2 mm. long; pod coiled --31.

30b. Flowers larger, each one 3-6 mm. long; pod straight (1-4 dm.
high) (Hop Clover) --32.

31a. Flowers numerous in each head =Black Medick, Medicago lupulina.=

31b. Flowers in clusters of 2 --20 =Bur Clover, Medicago hispida.=

32a. Stipules linear =Hop Clover, Trifolium agrarium.=

32b. Stipules ovate --33.

33a. Heads densely flowered; flowers 20 or more; upper petal striate
when dry =Hop Clover, Trifolium procumbens.=

33b. Heads loosely flowered; flowers usually 10 or fewer; upper petal
scarcely striate or not at all =Hop Clover, Trifolium dubium.=

34a. Leaves palmately compound, the 3 leaflets all from the same
point (late spring and summer) (Clover) --35.

34b. Leaves pinnately compound, the terminal leaflet on a distinct
stalk --39.

35a. Individual flowers sessile, or on very short pedicels --36.

35b. Individual flowers distinctly pedicelled --37.

36a. Heads oblong, on distinct peduncles; calyx longer than the
corolla (flowers nearly white; 1-4 dm. tall)
=Stone Clover, Trifolium arvense.=

36b. Heads nearly globose, almost sessile, closely subtended by the
leaves; corolla longer than the calyx (2-8 dm. high; flowers
red-purple) =Red Clover, Trifolium pratense.=

37a. Stems prostrate or creeping; heads long-peduncled, arising from the
creeping branches (flower-stalks 1-2 dm. high; flowers white)
=White Clover, Trifolium repens.=

37b. Some or all of the stems erect; heads arising from the leafy stems
(flowers white or pink) --38.

38a. Plants with long basal runners; flowers 10-13 mm. long (2-3
dm. high) =Buffalo Clover, Trifolium stoloniferum.=

38b. Basal runners none; flowers 6-8 mm. long (3-8 dm. high)
=Alsike Clover, Trifolium hybridum.=

39a. Prostrate; leaflets broadly ovate; flowers 3-10 in a cluster --10a.

39b. Erect; leaflets bro