One or perhaps 2 species distributed throughout the temperate parts of the northern hemisphere; the European and Asia plant is Andromeda polifolia*. North American plants are sometimes treated as a separate species, Andromeda glaucophylla, although the differences between the American plants and those from Eurasian populations are minor ones.
Andromeda was named by Carl Linnaeus: see E. C. Nelson 2007. Carl Linnaeus: a tercentenary celebration. Heathers 4: 1–3. polifolia refers to the foliage of a plant called 'Polium', and does not signify numerous leaves: see E. C. Nelson and P. H. Oswald, 2005. Polifolia revisited and explained. Huntia 12 (1): 5–11.