8. R. pusíllus, Poir. Stem ascending, weak, loosely branching (6–18´ long); leaves entire or obscurely denticulate, the lowest round-ovate or heart-shaped (½´ long), long-petioled, the upper oblong or lanceolate (1–1½´ long); flowers very small; petals 1–5, yellowish; stamens 3–10; carpels very turgid, smooth or slightly papillose, tipped with a minute sessile stigma.—Wet places, S. New York, and southward along the coast. June–Aug.
[+][+][+] Terrestrial, but often in wet places; leaves mostly cleft or divided.
[++] Root-leaves not divided to the very base; achenes marginless.
9. R. affìnis, R. Br. Somewhat hairy or glabrous; low or slender, 1° high or less; leaves pedately cleft, the cauline with linear or narrow oblanceolate divisions; petals light yellow, 3–4´´ long or smaller; heads oblong; achenes turgid, with small and mostly recurved style, pubescent or glabrous.—And var. validus, Gray, stouter and with more fleshy leaves, the lower mostly undivided and roundish, cordate, truncate or cuneate at base, coarsely crenate or more or less cleft.—Minn., Iowa, north and westward.
10. R. rhomboídeus, Goldie. Low (3–8´ high), hairy; root-leaves roundish or rhombic-ovate, rarely subcordate, toothed or crenate; lowest stem-leaves similar or 3–5-lobed, the upper 3–5-parted, almost sessile, the lobes linear; carpels orbicular with a minute beak, in a globose head; petals large, deep yellow.—Prairies, Mich. to N. Ill., Minn., and northward. April, May.
11. R. abortìvus, L. (Small-flowered C.) Biennial, glabrous, branching, 6´–2° high; primary root-leaves round heart-shaped or kidney-form, barely crenate, the succeeding often 3-lobed or 3-parted; those of the stem and branches 3–5-parted or divided, subsessile, the divisions oblong or narrowly wedge-form, mostly toothed; head globose; carpels mucronate, with a minute curved beak; petals pale yellow, shorter than the small reflexed calyx.—Shady hillsides and along brooks, common. April–June.
Var. micránthus, Gray. Pubescent, roots often fusiform-thickened; root-leaves seldom at all heart-shaped, some 3-parted or 3-divided; peduncles more slender and carpels fewer.—E. Mass. to Ill., Minn., and westward.
12. R. sceleràtus, L. (Cursed C.) Annual, glabrous; root-leaves 3-lobed, rounded; lower stem-leaves 3-parted, the lobes obtusely cut and toothed, the uppermost almost sessile, with the lobes oblong-linear and nearly entire; carpels barely mucronulate, very numerous, in oblong or cylindrical heads; petals scarcely exceeding the calyx.—Wet ditches; appearing as if introduced. June–Aug.—Stem thick and hollow, 1° high; juice acrid and blistering; leaves thickish; flowers small, pale yellow. (Eu.)
[++][++] Leaves variously cleft or divided; achenes in globular heads (except n. 17), compressed, with an evident firm margin; hirsute or pubescent.
[=] Achenes with long recurved beak; root-leaves rarely divided.