Historical biogeography of Euphorbia tithymaloides. A. This species expanded its geographic range from its area of origin in Mexico-Guatemala-Belize towards the Caribbean along two geographic fronts, one that extended through the Greater Antilles, and one that travelled south, then east, and then north through Central and South America, and the Lesser Antilles (drawn with information from Cacho et al. 2019). B. Representation of an allele phylogenetic tree of gene SGN-U342009 showing historic relationship between geographic fronts and subspecies. Colours: magenta, Euphorbia personata (sister species); green, E. tithymaloides subsp. tithymaloides (light green, Venezuelan accessions); purple, E. tithymaloides subsp. parasitica; navy, E. tithymaloides subsp. jamaicensis; yellow, E. tithymaloides subsp. bahamensis; red, E. tithymaloides subsp. angustifolia; cyan, E. tithymaloides subsp. padifolia (drawn with information from Cacho and Baum 2012).