ABSTRACT
The word "mistletoe" is about as nonspecific a term as you could possibly apply to a plant material. The addition of "American" or "European" helps a little. When properly used, American mistletoe refers to a single one of the more than 200 species of the genus Phoradendron. However, this species has four different scientific names, each of which is used more or less interchangeably. The most acceptable designation, of quite recent coinage, is Phoradendron leucarpum (Raf.) Rev. & M. C. Johnst., synonymous with P. serotinum (Raf.) M. C. Johnst. and P. flavescens (Pursh) Nutt. The nomenclature seems to be evolving more rapidly than the plant group itself. Once considered synonymous with P. tomentosum (DC.) Engelm, subspecies macrophyllum (Cockerell) Wiens, that taxon is now referred to as P macrophyllum (Engelm.) Cockerell subspecies macrophyllum.1,2 At first glance, the nomenclature for European mistletoe seems simpler; it is Viscum album L. But there are three subspecies commonly recognized: platyspermum Kell., growing on broadleaf trees; abietis Beck, growing on silver fir; and laxum Fiek, growing on various pines, seldom on firs.3 All of these plants are parasitic shrubs belonging to the family Viscaceae.
