Botanical Source and History.—This is the Viscum verticillatum of Nuttall, and Viscum album of Walter. It is a yellowish-green, succulent parasite, growing on the branches and trunks of old trees, especially apple trees, elms, oaks, hickories, etc. The stems are jointed, 1 or 1½ feet in length, rather thick, with many round, spreading, opposite, and sometimes verticillate, terete branches. The leaves are opposite, cuneate-obovate, 3-veined, obtuse, smooth, entire, contracted at the base into a short petiole, and 9 to 16 lines long by 4 to 9 broad. The flowers are small, greenish-white; the sterile ones mostly 3-parted, in axillary, solitary spikes, and about as long as the leaves. The fruit is globose, yellowish-white, smooth, semitransparent, with a viscous pulp, is borne in clusters, and contains 1 fleshy seed. It remains throughout the winter (W.—G.).
Viscum album, Linné, is the European species employed. It differs in the shape of its leaves, which are lance-shaped or spatulate. It grows upon apple, plum, pear and other fruit trees, as well as upon birches, beeches, poplars, etc.
Description.—This parasitic shrub is found growing on various trees; but that which is found on the oak is preferred. The bark and leaves have an unpleasant odor, and a mawkish, bitterish taste. The proper time for collection is in November, when it should be gradually dried, pulverized, and kept in a well-stoppered bottle. It should never be kept more than a year, as age impairs its active qualities. The mistletoe growing on the water or black elm (Ulmus nemoralis), and on the water oak (Quercus aquatica), is reputed to possess the most energetic medicinal virtues.