1. X. Canadénse, Mill. Stouter, the stem often brown-punctate; fruit about 1´ long, densely prickly and more or less hispid, the stout beaks usually hooked or incurved.--River-banks and waste places, common.--Var. ECHINÀTUM, Gray, usually low, with still denser and longer, conspicuously hirsute or hispid prickles. Sandy sea-shores and on the Great Lakes. 45. TETRAGONOTHÈCA, Dill. Heads many-flowered, radiate; the rays 6--9, fertile. Involucre double; the outer of 4 large and leafy ovate scales, united below by their margins into a 4-angled or winged cup; the inner of small chaffy scales, as many as the ray-flowers, and partly clasping their achenes. Receptacle convex or conical, with narrow and membranaceous chaff. Achenes very thick and obovoid, flat at the top; pappus none.--Erect perennial herbs, with opposite coarsely toothed leaves, their sessile bases sometimes connate, and large single heads of pale yellow flowers, on terminal peduncles. (Name compounded of τετράγωνος, _four-angled_, and θήκη, _a case_, from the shape of the involucre.) 1. T. helianthoìdes, L. Villous and somewhat viscid, 1--2° high, simple; leaves ovate or rhombic-oblong, sessile by a narrow base; involucral scales and rays about 1´ long.--Sandy soil, Va. and southward. June. 46. ECLÍPTA, L. Heads many-flowered, radiate; rays short; disk-flowers perfect, 4-toothed, all fertile. Involucral scales 10--12, in 2 rows, leaf-like, ovate-lanceolate. Receptacle flat, with almost bristle-form chaff. Achenes short, 3--4-sided, or in the disk laterally flattened, roughened on the sides, hairy at the summit; pappus none, or an obscure denticulate crown.--An annual rough herb, with slender stems and opposite leaves. Heads solitary, small. Flowers white; anthers brown. (Name from ἐκλείπω, _to be deficient_, alluding to the absence of pappus.) 1. E. álba, Hassk. Rough with fine appressed hairs; stems procumbent, or ascending and 1--3° high; leaves lanceolate or oblong, acute at each end, mostly sessile, slightly serrate; rays equalling the disk. (E. procumbens, _Michx._)--Wet river-banks, N. J. to Ill. and southward. Peduncles very variable. (All tropical countries.) 47. HELIÓPSIS, Pers. OX-EYE. Heads many-flowered, radiate; rays 10 or more, fertile. Involucral scales in 2 or 3 rows, nearly equal; the outer leaf-like and somewhat spreading, the inner shorter than the disk. Receptacle conical; chaff linear. Achenes smooth, thick, 4-angular, truncate; pappus none, or a mere border.--Perennial herbs, like Helianthus. Heads showy, peduncled, terminal. Leaves opposite, petioled, triple-ribbed, serrate. Flowers yellow. (Name composed of ἥλιος, _the sun_, and ὄψις, _appearance_, from the likeness to the Sunflower.)