[+] Calyx-teeth silky-plumose, longer than the whitish corolla; root annual.
T. arvénse, L. (Rabbit-foot or Stone Clover.) Silky, branching (5–10´ high); leaflets oblanceolate; heads becoming very soft-silky and grayish, oblong or cylindrical.—Old fields, etc. (Nat. from Eu.)
[+][+] Calyx scarcely hairy except a bearded ring in the throat, shorter than the rose-purple elongated-tubular corolla. (Short-lived perennials; flowers sweet-scented.)
T. praténse, L. (Red C.) Stems ascending, somewhat hairy; leaflets oval or obovate, often notched at the end and marked on the upper side with a pale spot; stipules broad, bristle-pointed; heads ovate, sessile.—Fields and meadows; largely cultivated. (Adv. from Eu.)
T. mèdium, L. (Zigzag C.) Stems zigzag, smoothish; leaflets oblong, entire, and spotless; heads mostly stalked; flowers deeper purple, otherwise too like the last.—Dry hills, N. Scotia to E. Mass. (Adv. from Eu.)
[*][*] Flowers pedicelled in umbel-like round heads on a naked peduncle, their short pedicels reflexed when old; corolla white or rose-color, withering-persistent and turning brownish in fading; the tubular portion short.
1. T. refléxum, L. (Buffalo C.) Annual or biennial; stems ascending, downy; leaflets obovate-oblong, finely toothed; stipules thin, ovate; standard rose-red, wings and keel whitish; calyx-teeth hairy; pods 3–5-seeded.—Western N. Y. and Ont. to Iowa, Kan., and southward.
2. T. stoloníferum, Muhl. (Running Buffalo-C.) Smooth, perennial; stems with long runners from the base; leaflets broadly obovate or obcordate, minutely toothed; heads loose; flowers white, tinged with purple; pods 2-seeded.—Open woodlands and prairies, Ohio and Ky., west to Iowa and Kan.
3. T. rèpens, L. (White C.) Smooth, perennial; the slender stems spreading and creeping; leaflets inversely heart-shaped or merely notched, obscurely toothed; stipules scale-like, narrow; petioles and especially the peduncles very long; heads small and loose; calyx much shorter than the white corolla; pods about 4-seeded.—Fields and copses, everywhere. Indigenous only in the northern part of our range, if at all.
4. T. Caroliniànum, Michx. Somewhat pubescent small perennial, procumbent, in tufts; leaflets wedge-obovate and slightly notched; stipules ovate, foliaceous; heads small on slender peduncles; calyx-teeth lanceolate, nearly equalling the purplish corolla; standard pointed; pods 4-seeded.—Waste ground near Philadelphia, south to Va., Fla., and Tex.