卤地菊 lu di ju

Wedelia prostrata Hemsley, J. Linn. Soc., Bot. 23: 434. 1888, based on Verbesina prostrata Hooker & Arnott, Bot. Beechey Voy. 195. 1837, not Linnaeus (1753); Eclipta dentata H. Léveillé & Vaniot; Melanthera robusta (Makino) K. Ohashi & H. Ohashi; W. prostrata var. robusta Makino; W. robusta (Makino) Kitamura; Wollastonia prostrata Hooker & Arnott (1838), not Candolle (1836).

Stems long creeping, rooting at nodes, coarsely hirsute; flowering branches ascending, leafy, densely strigose. Cauline leaves with 2-8 mm petiole, oblong, sometimes ovate or lanceolate, thickly leathery, coarsely strigose on both surfaces, 3-veined, base cuneate, margin loosely dentate, apex acute. Capitula 5-22 × 16-22 mm, usually solitary, terminal; peduncle 1-7 cm; involucre hemispheric, 10-12 × 5-6 mm; phyllaries 1-seriate, ovate to ovate-oblong, 2-3.5 mm wide, coarsely strigose, apex acute to obtuse. Ray corollas yellow, 8-11 × ca. 4 mm. Disk corollas tubular, 5-6 mm, 5-lobed. Achenes 3.5-4 × ca. 2 mm, apically strigillose, 3- or 4-angled; pappus bristles 1 or 2, or obsolete. 2n = 30.

Littoral sand dunes, sandy seashores. Guangdong, Taiwan [Japan, Korea, Thailand, Vietnam].

Wagner and Robinson (Brittonia 53: 557. 2001) noted that "Melanthera prostrata var. robusta Makino" (a combination that does not exist) is thought to represent a hybrid between M. prostrata and M. biflora (here treated as Wollastonia biflora), q.v. C. I Peng et al. (Fl. Taiwan, ed. 2, 4: 1094, 1097. 1998, as Wedelia prostrata var. robusta). This is not recognized here, q.v. Wagner and Robinson (loc. cit.).