What type of category does Echium and Oxydendrum have in common?
Echium Echium is a genus of 60 species of flowering plant in the family Boraginaceae.
Epidendrum tridens Epidendrum tridens ("the three-toothed "Epidendrum"") is a terrestrial orchid closely allied to "E. nocturnum", of which it has often been considered a variety or synonym. For example, Reichenbach 1861 lists "Epidendrum tridens" as a synonym of "Epidendrum nocturnum" and "Epidendrum nocturnum" var. "latifolium" as a distinguishable variety of "Epidendrum nocturnum".