3. B. cérnua, L. (SMALLER BUR-MARIGOLD.) Nearly smooth (5´--3° high), _leaves lanceolate, unequally serrate, scarcely connate; heads_ nodding, _with or without_ (light yellow) _rays_; outer involucre longer than the head; achenes wedge-obovate, 4-awned, the margins downwardly barbed.--Wet places, N. Eng. to Va., Mo., Minn., and northward. July--Sept.--Rays, if any, smaller than in n. 4, and the outer involucre more leaf-like. (Eu.) 4. B. chrysanthemoìdes, Michx. (LARGER BUR-MARIGOLD.) Smooth, erect, or reclining at the base (6´--2° high); _leaves lanceolate_, tapering at both ends, more or less connate, _regularly serrate_; outer involucre mostly shorter than the _showy golden-yellow (1´ long) rays_; achenes wedge-shaped, with almost prickly downwardly barbed margins; awns 2, 3, or 4.--Swamps; common. Aug.--Oct. [*][*] _Achenes linear, 4-sided, the inner longer and tapering upward._ 5. B. bipinnàta, L. (SPANISH NEEDLES.) Smooth annual, branched; leaves 1--3-pinnately parted, petioled; leaflets ovate-lanceolate, mostly wedge-shaped at the base; heads small, on slender peduncles; outer involucre of linear scales equalling the short pale yellow rays, achenes 4-grooved and angled, nearly smooth, 3--4-awned.--Damp soil, R. I. to N. Y., Ill., and southward. [*][*][*] _Achenes terete, truncate at both ends, with 3--6 very long awns smooth below._ 6. B. Béckii, Torr. (WATER MARIGOLD.) Aquatic, perhaps perennial, smooth; stems long and slender; immersed leaves crowded, capillary, many times dissected, the few emerging ones lanceolate, slightly connate, toothed; heads single, short-peduncled; involucre much shorter than the showy (golden yellow) rays; achenes thickish, smooth (½´ long), the stout divergent awns (1´ long) barbed only toward the apex.--Ponds and slow deep streams, Mass. to N. J., Mo., and northward. Aug.--Oct. 57. THELESPÉRMA, Less. Heads many-flowered; rays about 8, neutral, or none. Involucre as in Coreopsis, the inner connate to the middle, scarious-margined. Receptacle flat, the scarious chaff falling with the nearly terete wingless and beakless achenes; pappus of 2 stout subulate retrorsely hispid awns.--Smooth herbs, with opposite dissected leaves and pedunculate heads of yellow flowers. (From θηλή, _a nipple_, and σπέρμα, _seed_, on account of the papillose achenes.) 1. T. grácile, Gray. Perennial, rather rigid, 1--2° high; leaves with narrow or filiform divisions or the upper entire; outer scales very short; rays short or usually none; achenes papillose.--Kan., south and westward. 58. BALDWÍNIA, Nutt.