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.)
1. H. læ̀vis, Pers. Nearly smooth (1–4° high); leaves ovate-lanceolate or oblong-ovate, rather narrowly pointed, occasionally ternate; scales (as in the next) with a rigid strongly nerved base; rays linear; pappus none or of 2–4 obscure teeth.—Banks and copses, N. Y. to Ill. and southward. Aug.