Kruskal-Wallis tests on the first three morphology PC axes (that capture 96.7% of variation in leaf morphology) reveal significant differences in foliar morphology among subspecies of Euphorbia tithymaloides. A–C. Results from tests including all seven subspecies described for Caribbean E. tithymaloides. D–F. Results from tests that focus on the main three subspecies of this system (E. tithymaloides subspp. angustifolia, padifolia, and tithymaloides). Letters depict statistically different groups as identified by posthoc tests.