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.
Heads globular, many-flowered, radiate, the long and narrowly wedge-shaped rays neutral. Involucre short, of many thickish small scales imbricated in 3 or 4 rows, the outer obovate and obtuse. Receptacle strongly convex, with deep honeycomb-like cells containing the obconical or oblong silky-villous achenes; pappus of 7–9 lance-oblong erect chaffy scales.—A perennial herb, smoothish, with slender simple stems (2–3° high), bearing alternate oblanceolate leaves, and a large showy long-pedunculate head. Rays yellow (1´ long); the disk often turning dark purple. (Named for the late Dr. William Baldwin.)
1. B. uniflòra, Nutt.—Borders of swamps, Va. (?) and southward. Aug.
59. MARSHÁLLIA, Schreb.
Heads many-flowered; flowers all tubular and perfect, the corolla-lobes slender and spreading. Involucral scales linear-lanceolate, foliaceous, erect, in one or two rows, nearly equal. Receptacle convex or conical, with narrowly linear rigid chaff. Achenes top-shaped, 5-angled; pappus of 5 or 6 membranaceous and pointed chaffy scales.—Smooth and low perennials, with alternate entire 3-nerved leaves, and long-pedunculate heads (like those of a Scabious) terminating the simple stem or branches. Flowers purplish; anthers blue. (Named for Humphrey Marshall, of Pennsylvania, author of Arbustum Americanum, one of the earliest works on the trees and shrubs of this country.)
1. M. latifòlia, Pursh. Stems leafy; leaves ovate-lanceolate, pointed, sessile.—Dry soil, Va. and southward.