HELLEBORE, a genus (Helleborus) of plants of the family Ranunculaceae, natives of Europe and western Asia. They are coarse perennial herbs with palmately or pedately lobed leaves. The flowers have five persistent petaloid sepals, within the circle of which are placed the minute honey-containing tubular petals of the form of a horn with an irregular opening. The stamens are very numerous, and are spirally arranged; and the carpels are variable in number, sessile or stipitate and slightly united at the base and dehisce by ventral suture.
Helleborus niger, black hellebore, or, as from blooming in mid-winter it is termed the Christmas rose, is found in south ern and central Europe, and with other species was cultivated in the time of Gerard (see Herball, p. 977, ed. Johnson, 1633), in English gardens. Its knotty root-stock is blackish-brown externally, and, as with other species, gives origin to numerous straight roots. The leaves spring from the top of the root-stock, and are smooth, distinctly pedate, dark-green above, and lighter below, with 7 to 9 segments and long petioles. The scapes, which end the branches of the rhizome, have a loose entire bract at the base, and termi nate in a single flower, with two bracts, from the axis of . one of which a second flower may be developed. The flowers have 5 white or pale-rose, eventually greenish sepals, 15 to 18 lines in breadth ; 8 to 13 tubular green petals containing honey ; and 5 to 1 o free carpels. There are several forms, the best being maximus. The Christmas rose is extensively grown in many market gardens to provide white flowers about Christmas time for decorations.
H. orientalis, the Lenten rose, has given rise to several fine hybrids with H. niger, some of the best forms being clear in colour and distinctly spotted. H. f oetidus, stinking hellebore, is a native of England, where like H. viridis, it is confined chiefly to limestone districts ; it is common in France and the south of Europe. Its leaves have 7- to I I -toothed divisions, and the flowers are in panicles, numerous, cup-shaped and drooping, with many bracts, and green sepals tinged with purple, alternating with the five petals.
H. viridis, or green hellebore proper, is probably indigenous in some of the southern and eastern counties of England, and occurs also in central and south ern Europe. It has bright yellow ish-green flowers, 2 to 4 on a stem, with large leaf-like bracts. 0. Brunfels and H. Bock (16th century) regarded the plant as the black hellebore of the Greeks.
H. lividus, holly-leaved helle bore, found in the Balearic Is lands, and in Corsica and Sardinia, is remarkable for the handsome ness of its foliage. White helle bore is Veratrum album (see VERATRUM), a liliaceous plant.
The rhizome of H. niger oc curs in commerce in irregular and nodular pieces, from about i to 3 in. in length, white and of a horny texture within. Cut trans versely it presents internally a circle of 8 to 12 cuneiform lig neous bundles, surrounded by a thick bark. It emits a faint odour when cut or broken, and has a bitter and slightly acrid taste. The drug is sometimes adulter ated with the rhizome of baneberry, Actaea spicata, which, how ever, may be recognized by the distinctly cruciate appearance of the central portion of the attached roots when cut across, and by its decoction giving the chemical reactions for tannin. The rhizome is darker in colour in proportion to its degree of dry ness, age and richness in oil.
H. niger, orientalis, viridis, foetidus, and several other species of hellebore contain the glucosides helleborin, and lielle bore'in, C26H44015, the former yielding glucose and lielleboresin, and the latter glucose and a violet-coloured substance helleboretin, Helleborin is most abundant in H. viridis. A third and volatile principle is probably present in H. f oetidus. Both helleborin and helleborein act poisonously on animals.