- Viscum, genus Viscum - type genus of the Viscaceae: Old World evergreen shrubs parasitic on many trees including oaks but especially apple trees, poplars, aspens and cottonwoods
--1 is a kind of dilleniid dicot genus
--1 is a member of Viscaceae, family Viscaceae, mistletoe family
--1 has members: mistletoe, Viscum album, Old World mistletoe