Monographs Details: Wedelia trilobata (L.) Hitchc.
Authority: Britton, Nathaniel L. Flora Borinqueña.
Description:Species Description - With long-stalked heads of bright yellow flowers, borne on trailing, or decumbent stems and branches, this low herbaceous plant is one of the attractive native species of Porto Rico, inhabiting fields, and banks at lower and middle elevations, usually in wet or moist soil. It grows in such situations nearly all over the West Indies, ranging north into Florida, and on the continent from Honduras to Colombia. Wedelia, a genus established by Jacquin in 1760, consists of some 50 species of herbs and shrubs, natives of tropical and warm-temperate regions, the name was given in honor of Georg Wolfgang Wedel, Professor in Jena, who lived from 1645 to 1721. Their leaves are opposite. Their flowers, both discoid and radiate, are in stalked heads, the involucre with few bracts in about 2 series, the receptacle bearing scales which envelope the disk-flowers; the ray-flowers are pistillate, the disk-flowers perfect.The achenes are oblong or obovate, and bear a cup-like, toothed pappus, or none. Wedella trilobata (leaves sometimes 3-lobed) is nearly smooth, somewhat fleshy, and trails on the ground, from 0.3 to 1 meter in length, often sending out roots from the nodes of the stem, the branches sometimes ascending. The nearly stalkless, elliptic to obovate leaves, from 2 to 12 centimeters long, are toothed, or variously lobed, narrowed at the base. The flower-heads are solitary, on axillary stalks from 2 to 14 centimeters long; the involucre, composed of about 5 oblong-obovate bracts, is from 8 to 12 millimeters long; there are about 10, bright yellow rays from 10 to 15 millimeters long, the achenes are about 5 millimeters long, conic at the top, tubercled. There are 5 other Wedelias in the Porto Rico Flora.

Discussion:Manzanilla Trailing Wedelia Thistle Family Silphium trilobatum Linnaeus, Systema Naturae, edition 10, 1233. 1859. Wedelia carnosa l. C. Richard, in Persoon, Synopsis Plantarum 2: 490.1807. Wedelia trilobata Hitchcock, Annual Report of the Missouri Botanical Garden 4: 99. 1893.