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 RHODODENDRON RHONE 301 are silvery white beneath, and the large clus- ters of flowers are scarlet, varying, even in the wild state, through various shades to pure white. The catalogue of varieties is a long one, but they can only be cultivated in the northern states, as in England, under glass, where, when room can be afforded, they make a most brilliant show. Other exotic species seen in rare collections are the yellow-flowered (R. chrysanthum), from the Caucasus ; the hairy (R. hirsutum), very dwarf, with pale red flowers ; and the Daurian (R. Dauricum), from Siberia, a dwarf species with bright rose- purple and very early flowers ; these three are hardy. A magnificent group of rhododen- drons is found in the Himalaya, presenting a great variety in foliage and flowers, as well as habit of growth, some of them being epi- phytes ; they require to be cultivated under glass, both here and in Europe ; the majority of these were first made known by Dr. J. D. Hooker, to whose work, " The Rhododendrons of the Sikkim Himalaya," reference may be made for descriptions and colored plates of these wonderfully beautiful plants. The rho- dodendrons of our gardens are known as hy- brids of R. Catawbiense ; European horticul- turists have long practised hybridizing this species with R. arboreum, R. Ponticum, and possibly others; among these hybrids are many very beautiful varieties which do not endure northern winters, requiring to be housed ; but there are several perfectly hardy varieties, which some experienced cultivators think are not hybrids at all, but merely seed- ling variations of R. Catawbiense. Especial attention is given to these plants in England, and their popularity in this country is in- creasing. For beauty of form and foliage and profusion and variety in flowers no oth- er shrubs can equal them. Their general cul- tivation has been hindered by the supposition that they require a peat soil; but the plants, at least those raised in this country, will flourish perfectly well in any good garden soil that is not calcareous ; they will not succeed in a heavy clay or on a limestone soil. The varieties are numbered by hundreds ; twelve well tested sorts are : grandiflorum, album elegans, roseum elegans, Everestianum, album grandiflorum, giganteum, Lee's dark purple, gloriosum, macranthum, purpureum elegam, candidmimum, and speciosum. The rhodo- dendrons are exceedingly manageable plants ; they may be taken up at almost any time with- out injury, and when in full bloom may be lifted and used for the decoration of rooms, and set out again without showing the effects of the disturbance. In England the common- er seedlings are largely planted to form game coverts. But little positive is known about the active properties of our native rhododen- drons; narcotic powers are attributed to R. maximum, while others regard it as a simple astringent ; Michaux says that R. punctatum yields a honey that is deleterious, but this statement needs confirmation. The informa- tion in regard to exotic species is hardly more definite ; the yellow-flowered rhododendron is said to be narcotic and dangerous. In India the natives eat the flowers of R. arbor eum, and European residents prepare a conserve from them ; this species secretes honey in such quantities that when the bush is shaken it falls like rain in large drops. RHODOPE. See THBAOE. RHODORA (Gr. f>66ov, a rose, from the color of the flowers), a native shrub of which the botanical and common names are the same. R. Canadensis is the only species, and is by some botanists appended to rhododendron, from which it differs in its deciduous leaves and its very irregular flowers, the corolla be- ing two-lipped, the upper lip three-lobed, and the lower two-parted, or of two distinct spreading petals. The shrub is 1 to 3 ft. high, with copper-colored stems and oblong leaves, Bhodora Canadensis. revolute on the margin, pale glaucous green above, and whiter and downy beneath. The flowers, in umbel-like clusters, or little tufts, at the ends of the branches, appear just before the leaves, and are of a bright rose-purple and showy ; occasionally white-flowered speci- mens are met with. It is found from Penn- sylvania to New England and northward and eastward ; it sometimes grows in damp cold mountain woods, but more abundantly in wet marshes, where, especially in the vicinity of Boston, it sometimes covers acres in April or May, with its bright yet modest bloom. Like many other plants, which when growing wild are always found in very wet places, the rho- dora succeeds well when transferred to or- dinary garden soil, and is a shrub eminently worthy of cultivation. RHONE (anc. Rhodanus), a river of Europe, rising in the N. E. corner of the Swiss canton of Valais, not far from the sources of the Rhine, and flowing into the gulf of Lyons in