dwarf rose-bay; a genus of the monogynia order, belonging to the decandra class of plants. There are six species; the most remarkable of which are, 1. The hirsutum, with naked hairy leaves, grows naturally on the Alps and several mountains of Italy. It is a low shrub, which seldom rises two feet high, sending out many ligneous branches covered with a light-brown bark, garnished closely with oval spear-shaped leaves, sitting pretty close to the branches. They are entire, having a great number of fine iron-coloured hairs on their edges and under-side. The flowers are produced in bunches at the end of the branches, having one funnel-shaped petal cut into five obtuse segments, and of a pale-red colour. 2. The ferrugineum, with smooth leaves, hairy on their under-side, is a native of the Alps and Apennines. It rises with a shrubby stalk near three feet high, sending out many irregular branches covered with a purplish bark, and closely garnished with smooth spear-shaped entire leaves, whose borders are reflexed backward; the upper-side is of a light lucid green; their Rhododendron under-side of an iron colour. The flowers are produced at the ends of the branches, are funnel-shaped, cut into five segments, and of a pale rose colour.—These plants are propagated by seeds; but, being natives of barren rocky soils and cold situations, they do not thrive in gardens, and for want of their usual covering of snow in the winter are often killed by frost in this country.

In Siberia, a species of this plant is used with great success in gouty and rheumatic affections, of which the following account is given in the 5th volume of the Medical Commentaries, p. 434, in a letter from Dr Guthrie of Petersburg to Dr Duncan of Edinburgh. "It is the rhododendrum chrysanthemum, nova species, belonging to the class of decandra, discovered by professor Pallas in his tour thro' Siberia. This Alpine shrub grows near the tops of the high mountains named Sajaner, in the neighbourhood of the river Jenise in Siberia; and delights in the skirts of the snow-covered summits, above the region that produces trees. When the inhabitants of that country mean to exhibit it in arthritic or rheumatic disorders, they take about two drams of the dried shrub, stalk and leaves, with nine or ten ounces of boiling water, and putting them into an earthen pot, they lute on the head, and place them in an oven during the night. This infusion, for it is not allowed to boil, the sick man drinks next morning for a dose. It occasions heat, together with a degree of intoxication, resembling the effects of spirituous liquors, and a singular kind of uneasy sensation in the parts affected, accompanied with a sort of vermiculation, which is likewise confined to the diseased parts. The patient is not permitted to quench the thirst which this medicine occasions, as fluids, particularly cold water, produce vomiting, which lessens the power of the specific. In a few hours, however, all the disagreeable effects of the dose disappear, commonly with two or three stools. The patient then finds himself greatly relieved of his disorder, and has seldom occasion to repeat the medicine above two or three times to complete a cure. The inhabitants of Siberia call this shrub chei, or tea, from their drinking, in common, a weak infusion of it, as we do the Chinese plant of that name. This practice shows, that the plant, used in small quantities, must be innocent. Professor Pallas informs me, that he sent some time ago, some of this shrub dried to professor Koepin at Stetin; and he showed me a letter from that gentleman, where he says, that he has given it with success in several cases, particularly in what he calls the arthritis venerea, with a tophus arthriticus on the carpus, and it produced a complete cure. It must be remarked, that the dose which these hardy Siberians take, who are also in the habit of drinking it as tea, would, in all probability, be too strong for our countrymen; however, it is a medicine which we may certainly give with safety, beginning with small doses."

RHŒADEÆ (rōsæ, Linnaeus's name after, Dioscorides, for the red poppy), the name of the 27th order in Linnaeus's fragments of a natural method, consisting of poppy and a few genera which resemble it in habit and structure. See BOTANY, p. 1309.

RHOMBOIDES in geometry, a quadrilateral figure whose opposite sides and angles are equal, but is neither equilateral nor equiangular.