Erect perennial mostly branched herbs, with opposite, sessile or connate-perfoliate, broad dentate leaves, and large peduncled heads of tubular and radiate yellow flowers. Involucrte depressed-hemispheric, its principal bracts 4, large and foliaceous, inserted in 1 series; inner bracts 6-15, small, subtending the pistillate ray-flowers. Receptacle conic, chaffy, the chaff concave, enwrapping the perfect fertile disk-flowers, the corollas of which are slender and S-toothed. Anthers entire or minutely 2-toothed at the base. Style-branches of the disk-flowers hispid, tipped with elongated appendages. Achenes thick, 4-sided, truncate at the summit. Pappus none, or of several short scales. [Greek, 4-angled-case, referring to the involucre.]

Four known species, natives of the southern United States and northern Mexico, the following typical.

1. Tetragonotheca Helianthoides L. Tetragonotheca

Fig. 4440

Tetragonotheca helianthoides L. Sp. Pl. 903. 1753.

Viscidly pubescent; stem brancned or simple, 1°-2 1/2° high Leaves ovate, ovate-oblong, or somewhat rhomboid, thin, coarsely and unequally dentate, pinnately veined, acute at the apex, narrowed at the sessile or somewhat clasping base, 2'-6' long, i'-j' wide; heads usually few, 11/2'-3' broad; involucre 4-angled in the bud, its principal bracts broadly ovate, acute; rays 6-10, strongly parallel-nerved, 2-3-toothed; corolla-tube villous below; achenes 4-sided, or nearly terete; pappus none.

In dry soil, Virginia to Tennessee, Florida and Alabama. May-June. Sometimes flowering again in autumn.

1 Tetragonotheca Helianthoides L Tetragonotheca 1111