What type of category does Echium and Oxydendrum have in common?
Oxydendrum Sourwood or sorrel tree, Oxydendrum arboreum, is the sole species in the genus Oxydendrum, in the family Ericaceae. It is native to eastern North America, from southern Pennsylvania south to northwest Florida and west to southern Illinois; it is most common in the lower chain of the Appalachian Mountains. The tree is frequently seen as a component of oak-heath forests.
Erythroxylum Erythroxylum ("Erythroxylon") is a genus of tropical flowering plants in the family Erythroxylaceae. Many of the approximately 200 species contain the drug cocaine; "Erythroxylum coca", a native of South America, is the main commercial source of cocaine and of the mild stimulant coca tea. Another species, "Erythroxylum vacciniifolium" (also known as Catuaba) is used as an aphrodisiac in Brazilian drinks and herbal medicine.