This parasitic growth, with its white berries, is more heavily loaded with Paganism than any other Christmas emblem. As far back as history goes, it has been held in superstitions awe. Early Christians hated it and by canon law they rigorously excluded it from church decorations. To this day many orthodox Christian clergy regard it as incorrect, if not blasphemous, to place it within a church. The mistletoe has an ancient connexion with fertility rites, as the custom of kissing under the mistletoe dimly commemorates. The continuance of such kissing reflects a triumph for tradition. The ancient British Druids, according to the Roman naturalist, Pliny, used the juice as an aphrodisiac and a cure for sterility. More widely, it was used as a semi-magical cure for a variety of ailments. Even today it is used by practitioners of witchcraft as one of their staple emblems.

In the Middle Ages, Christians tried to bring it within their system by devising the legend that the mistletoe was once a proper tree—the one used by the Romans for Jesus’s cross. As a punishment it was shrivelled up and made parasitic. The creation of this legend illustrates the deep antipathy felt towards a plant that was widely regarded as an evil growth. Yet, in spite of long centuries of censure and disapproval on the part of officialdom, mistletoe has stubbornly held its own as a midwinter decoration.