28b. Flowers in loose racemes or panicles --42.
29a. Flowers bright-yellow; dec.u.mbent 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 Med.i.c.k, Medicago lupulina.=
31b. Flowers in cl.u.s.ters 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 proc.u.mbens.=
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 cl.u.s.ter --10a.
39b. Erect; leaflets broadest near the middle; flowers numerous (5-12 dm. high; flowers yellowish-white, late summer) (Bush Clover) --40.
40a. Leaflets less than twice as long as broad =Bush Clover, Lespedeza hirta.=
40b. Leaflets more than twice as long as broad --41.
41a. Leaflets linear, 5 mm. wide or less; heads with obvious peduncles =Bush Clover, Lespedeza angustifolia.=
41b. Leaflets narrowly elliptical, the princ.i.p.al ones more than 5 mm.
wide; heads sessile or nearly so =Bush Clover, Lespedeza capitata.=
42a. Leaflets finely toothed --43.
42b. Leaflets entire --44.
43a. Flowers violet or blue (3-6 dm. high; summer) =Alfalfa, Medicago sativa.=
43b. Flowers yellow (1-2 m. high; summer) =Yellow Sweet Clover, Melilotus officinalis.=
43c. Flowers white (1-3 m. high; summer) =White Sweet Clover, Melilotus alba.=
44a. Flowers yellow (5-10 dm. high; summer) =Wild Indigo, Baptisia tinctoria.=
44b. Flowers white, the leaflets all from the same point (5-10 dm.
high; summer) =Wild Indigo, Baptisia leucantha.=
44c. Flowers blue, purple, or pink (rarely white, and then the terminal leaflet stalked) --45.
45a. Racemes arising from the base of the plant, leafless (4-8 dm. high; summer) =Tick Trefoil, Desmodium nudiflorum.=
45b. Racemes terminal or a few of them axillary; leaflets generally more than 3 cm. long; pod (usually to be seen at the base of the raceme) transversely segmented into 2 or more joints (summer) (Tick Trefoil; the genus Desmodium. Pods are usually necessary for satisfactory identification) --46.
45c. Racemes short, loose, chiefly axillary; leaflets generally less than 3 cm. long; the short ovate or ovoid pod not transversely jointed (5-10 dm. high; flowers in summer) (Bush Clover; the genus Lespedeza. Reference to the Manual is recommended) --58.
46a. Leaves cl.u.s.tered near the summit of the stem (4-12 dm. high) =Tick Trefoil, Desmodium grandiflorum.=
46b. Leaves scattered on the stem --47.
47a. Plants prostrate; racemes panicled; leaflets nearly circular =Tick Trefoil, Desmodium rotundifolium.=
47b. Plants dec.u.mbent or ascending; racemes short, simple, few-flowered; stipules ovate (stems 4-8 dm. long) =Tick Trefoil, Desmodium pauciflorum.=
47c. Plants erect or ascending; racemes panicled --48.
48a. Leaflets of an oblong type, broadest at or near the middle, and about 4 times as long as broad (5-10 dm. tall) --49.
48b. Leaflets of an ovate or lanceolate type, broadest below the middle, and not more than 3 times as long as wide --50.
49a. Stem p.u.b.escent; leaves sessile or nearly so =Tick Trefoil, Desmodium sessilifolium.=
49b. Stem glabrous or nearly so; leaves obviously petioled =Tick Trefoil, Desmodium paniculatum.=
50a. Stipules lanceolate to ovate, 1 cm. long or more (6-15 dm.
high) --51.