E. fosbergii is an annual, erect or ascending herb, branched, 20 to 50 cm (up to 100 cm) tall. Stems glabrous to sparsely pilose or sometimes prominently villous-pilose near the axils of the middle cauline leaves. Leaves alternate, broadly ovate to oblanceolate, often tapering to a prominently winged petiole and therefore appearing pandurate, the base sessile to auriculate, the margin weakly serrate to dentate or sometimes lobed, the teeth callose-tipped, overall 5-10 cm long, 2-5 cm wide, about 2 times longer than wide, the uppermost leaves reduced to linear serrate clasping bracts. Inflorescence of one to several headed, loose, corymbiform cymes arising terminally or laterally in the axils of the upper cauline leaves. Heads turbinate or sometimes weakly urceolate or becoming weakly campanulate in age, robust, 2-3 times longer than wide, the florets prominently exserted approximately 2 mm beyond the involucre;involucral bracts 8-13, linear, (7-) 9-12 mm long;receptacle flat to convex, the carpopodia forming prominent tubercles after achenes have been shed;florets 15-30, varying greatly in size with the robustness of the plant, the corollas pink to light purple or red but not orange. Achene reddish brown to light tan, columnar, approximately 5 mm long with a row of strigose-hirsute pubescence on each of the 5 prominent ribs;pappus of abundant, white, capillary hairs (Flora of Taiwan Editorial Committee, 2014;Missouri Botanical Garden, 2014).
Related invasive species
- Emilia fosbergii
Related Farm Practice
- Light
- Hosts
- Flora
- Plantations
E. fosbergii is a cosmopolitan annual herb included in the Global Compendium of Weeds (Randall, 2012). It is fast-growing, with the capacity to grow as a weed and colonize disturbed areas, waste ground, gardens, abandoned farmland, coastal forests, forest edges, pastures, roadsides, rocky areas, and riverbanks (Wagner et al., 1999;Vibrans, 2011;Pruski 2014). It produces large amounts of wind-dispersed seeds (5000 seeds per plant;Mejía et al., 1994) which is a feature facilitating the likelihood of spreading and colonizing new habitats. Currently, E. fosbergii is listed as invasive in Mexico, Central America, West Indies, and on several islands in the Pacific Ocean (see Distribution Table for details).
E. fosbergii has been listed as a weed in rice plantations in Colombia and coffee plantations in Costa Rica. It is also listed as a weed in cassava and sugarcane plantations in Central and South America (Echegoyen-Ramos et al., 1996, Murillo et al., 2006;Vibrans, 2011).