黄花紫背草 huang hua zi bei cao

Herbs, annual. Stems erect or ascending, to 140 cm tall, glabrous or pilose. Basal and lower stem leaves petiolate; petiole 1.5-3 cm, in basal leaves unwinged and exauriculate, in lower stem leaves winged and basally auriculate; blade broadly ovate, 4-6 × 4.5-6 cm, ± pilose, base subcordate, margin dentate, apically obtuse; median and upper stem leaves sessile, pandurate to triangular, becoming smaller upward. Capitula up to 7 in lax corymbs, rarely solitary. Involucres cylindric, ca. 10 × 3-4 mm; phyllaries 9-12. Florets distinctly exceeding involucre; corollas cream, yellowish, or pallid orange, ca. 8 mm; lobes ca. 2 mm, tinged purple or orange. Achenes ca. 3 mm, pubescent. Pappus ca. 7 mm. 2n = 20.

Disturbed places. N Taiwan [W tropical Africa].

Emilia praetermissa is presumably introduced, an allotetraploid of hybrid origin (Emilia sonchifolia var. sonchifolia × E. lisowskiana C. Jeffrey, the latter previously identified as E. coccinea).