Pucker up! The holidays won't be complete without a sprig of mistletoe hung in the doorway to invite yuletide kisses. (Mistletoe lore is connected with the European plant, Viscum alba, but the traditions have been transferred to the North American mistletoes, which belong to the genus Phorodenron). Hanging a sprig in the doorway goes back to the Druids, who called the herb "all-heal" and considered it sacred. At the winter solstice, mistletoe was cut from the sacred oak with a ritual knife and caught in a white cloth so that it did not touch the ground. Hung in a doorway, it protected the home from evil spirits during the darkest time of the year and created a sanctuary where a kiss of peace could be exchanged. In Victorian times, every kiss required the plucking of a white berry. When the berries were gone, lovers were out of luck.

Medicinally, mistletoe has been used to treat convulsions, hysteria, neuralgia, and heart conditions. Recent research suggests that European mistletoe may also inhibit the growth of tumors and hence be useful in cancer treatment. (Scientists say that the berries aren't poisonous, as has been thought. But it's still not a good idea to eat them.)