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._ 13. R. recurvàtus, Poir. (HOOKED C.) Hirsute, 1--2° high; leaves of the root and stem nearly alike, long-petioled, deeply 3-cleft, large; the lobes broadly wedge-shaped, 2--3-cleft, cut and toothed toward the apex; petals shorter than the reflexed calyx, pale.--Woods, common. May, June. [=][=] _Style long and attenuate, stigmatose at the tip, persistent or the upper part usually deciduous; early root-leaves only 3-parted, the later 3--5-foliolate; petals bright yellow, much larger than the calyx (except n. 18)._ 14. R. fasciculàris, Muhl. (EARLY C.) Low, ascending, 5--9´ high, pubescent with close-pressed silky hairs; _root a cluster of thickened fleshy fibres; radical leaves appearing pinnate_, the long-stalked terminal division remote from the sessile lateral ones, itself 3--5-divided or parted and 3--5-cleft, the lobes oblong or linear; petals often 6 or 7, spatulate-oblong, twice the length of the spreading calyx; _carpels scarcely margined_, tipped with a slender straight or rather curved beak.--Dry or moist hills. April, May.