A plant species of the family VISCACEAE, order Santalales, subclass Rosidae. This is the traditional mistletoe of literature and Christmas. Members contain viscotoxin (5 kDa basic polypeptides related to thionins), beta-galactoside- and N-acetyl-D-galactosamine-specific lectin II (60 kDa), and polysaccharides. Mistletoe lectin I is a type 2 ribosome-inactivating protein. Commercial extracts include Plenosol, Eurixor, Helixor Isorel, Iscador, and NSC 635089 (ANTINEOPLASTIC AGENTS, PHYTOGENIC).