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Tridax (From Thridax the old Greek)

(from Thridax, the old Greek name used by Dioscorides for the Lettuce, from treis, three, and akis, a point; alluding to the ray florets). SYNS. Balbisia (of Willdenow), Bartolina. Including Galinsogea and Ptilostephium. ORD. Compositae. A genus embracing seven species of hardy, perennial herbs, natives of tropical America. Flower-heads yellow, or the disk greenish, mediocre, long-peduncualte, heterogamous; ray florets ligulate or sub-bilabiate, the outer lip large, sometimes three-toothed, three-cleft, or three-parted, the inner smaller or minute, two-lobed or two-parted, sometimes obsolete; involucral bracts in few series; receptacle flat or convex; achenes turbinate, silky-villous. Leaves opposite, incised-toothed or pinnately dissected; segments few, narrow. The species possess but little beauty, and require ordinary culture. Propagated by divisions, or by seeds. T. coronopifolium (Coronopus-leaved). fl.-heads yellow; ray florets unequally five-lobed; outer involucral scales obtuse or mucronate. June. l. variously pinnatifid or trifid; lobes linear, acute. h. 1ft. Mexico. SYN. Ptilostephium coronopifolium.

T. trilobata (three-lobed). fl.-heads yellow; ray florets five-toothed; pappus bristles very short and scarcely pinnately lobed, or longer and plumose-fimbriate; peduncles pubescent or glandular-puberulous at apex. June. l. three-lobed or pinnately incised. h. 1ft. Mexico. SYN. Galinsogea trilobata (B. M. 1895; S. B. F. G. 56).