Calyx-teeth small or obsolete. Fruit ovate, glabrous; carpel with dorsal ribs filiform to broad and obtuse, the lateral very thick and corky, those of the two carpels closely contiguous and forming a dilated obtuse or acute corky band; oil-tubes solitary, stylopodium conical; seed nearly terete.--Smooth branching annuals, with finely dissected leaves, involucre of foliaceous bracts, involucels of prominent or minute bractlets, and white flowers. (Name from δίσκος, _a disk_, and πλευρόν, _a rib_.) 1. D. capillàcea, DC. Plant 1--2° high (or even 5--6°); leaves dissected into filiform divisions; umbel 5--20-rayed, involucre of filiform bracts usually cleft or parted, and involucels more or less prominent, fruit 1--1½´´ long, ovate, acute.--Wet ground, Mass. to Fla., west to Ill., Mo., and Tex. June--Oct. 2. D. Nuttàllii, DC. Similar in habit; involucral bracts short and entire; fruit very small (½´´ long), as broad as high, blunt.--Ill. (?) to Ark., La., and Tex. 30. CONÌUM, L. POISON HEMLOCK. Calyx-teeth obsolete. Fruit ovate, somewhat flattened at the sides, glabrous, with prominent wavy ribs; oil-tubes none, but a layer of secreting cells next the seed, whose face is deeply and narrowly concave.--Poisonous biennial, with spotted stems, large decompound leaves with lanceolate pinnatifid leaflets, involucre and involucels of narrow bracts, and white flowers. (Κώνειον, the Greek name of the Hemlock, by which criminals and philosophers were put to death at Athens.) C. MACULÀTUM, L. A large branching European herb, in waste places, N. Eng. to Penn., and west to Iowa and Minn. 31. CHÆROPHÝLLUM, L. Calyx-teeth obsolete. Fruit narrowly oblong to linear, notched at base, with short beak or none, and equal ribs; oil-tubes solitary in the intervals, seed-face more or less deeply grooved.--Moist ground annuals, with ternately decompound leaves, pinnatifid leaflets with oblong obtuse lobes, mostly no involucre, involucels of many bractlets, and white flowers. (Name from χαίρω, _to gladden_, and φύλλον, _a leaf_, alluding to the agreeable odor of the foliage.) 1. C. procúmbens, Crantz. More or less hairy; stems slender, spreading (6--18´ high); umbels few-rayed; fruit narrowly oblong (2½--3½´´ long), glabrous, contracted but not tapering at the summit, the intervals broader than the ribs.--N. Y. to N. C., west to Mich., Iowa, Ark., and Miss. Var. Shórtii, Torr. & Gray, has more broadly oblong to ovate (often somewhat pubescent) fruit, not at all contracted at the summit.--Ky. to Ark. and La. 32. OSMORRHÌZA, Raf. SWEET CICELY.