Page:The American Cyclopædia (1879) Volume XIV.djvu/316

 300 RHODODENDRON solutions slowly forms a brown sulphide. Rhodium salts heated in a current of hydrogen gas are reduced to the metallic state. RHODODENDRON (Gr. fio666evdpov, rose tree, the ancient name), a genus of plants of the order ericacece or heath family, to which the name rose bay has been given, but the botani- cal name is in more common use. The rhodo- dendrons are shrubs or low trees with ever- green, entire, alternate leaves, and (usually) large showy flowers in close terminal clusters, from large scaly-bracted buds. The bell-shaped or funnel-shaped corolla is five-lobed, and often somewhat irregular ; the ten stamens (rarely less) are usually declined or bent down- ward, as is the elongated style ; anthers short, opening by terminal pores; pod five-celled, five-valved, and many-seeded. The genus is widely distributed, some species occurring in the arctic zone, others in the temperate por- tions of North America, still others in Europe and China, while in the mountains of India they are very numerous. Four species are found east of the Mississippi, one of which, the Lapland rhododendron (R. Lapponicum), belongs to the arctic flora of both continents, and with us is found only on the alpine sum- mits of the mountains of Maine, New Hamp- shire, and New York ; it is a little, dwarf, prostrate species, with branches only a few inches long, its stems and leaves dotted with rusty scales ; the flowers are open, bell-shaped, violet purple and dotted. The great rhodo- dendron (R. maximum), aUo called great lau- rel, is found sparingly from Maine to Ohio, but is very common in the mountains of the Hybrid of Rhododendron Catawbiense. middle states, and along the watercourses as far south as Georgia; it flourishes best in deep, damp woods, and in cedar swamps it often forms the principal undergrowth. It is from 6 to 20 ft. high, with the habit of a shrub rather than of a tree. The leaves are very thick and leathery, from 4 to 10 in. long, elliptical-oblong, acute, narrowed toward the base, somewhat revolute or turned over on the margins, very smooth, and dark green. The flowers appear in July in large clusters, with somewhat viscid stalks ; the corolla is an inch broad, white or pale rose-colored, and green- ish at the throat on the upper side and spot- ted with yellow or reddish dots ; a variety is sometimes met with having pure white and one with purplish flowers. This species is not common in cultivation, and succeeds best in a shaded situation ; some hybrids have been produced from it, but very few in number compared with those from the next. The Catawba rhododendron (R. Catawliense) grows on the higher Alleghanies from Virginia to Georgia. It is a compact shrub, from 3 to 6 ft. high ; its oval or oblong leaves are rounded at both ends, pale beneath, and 8 to 5 in. long; the broadly bell-shaped flowers are lilac pur- ple, and on (usually) rusty-downy stalks. This species, hybridized with tender exotic species, is the original of the fine ornamental rhodo- dendrons to be mentioned presently. The dotted rhododendron (R. punctatum) com- pletes the list of the eastern native species ; this is found from the mountains of North Carolina southward, a small-leaved form oc- curring in West Florida. It grows 4 to 6 ft. high, has leaves 2 to 4 in. long, and, though evergreen, thinner than in the other species, and their lower surface, as well as branchlcts, and outside of the flowers, sprinkled with rusty dots; the flowers are rather small and rose-colored. Two species, both first described and figured by Sir William Hooker, occur in the far west. The white-flowered rhododen- dron (R. alliflorum), first found on the Rocky mountains, and since on the Cascade range, is a low shrub with drooping cream-colored flowers, unlike those of others in appearance. The Calif ornian species (R. Caltfornicum), from the mountains of California, has proved hardy in England, and is described as of mod- erate size, good habit, and having very showy rose-colored flowers. The most important ex- otic species is the Pontic rhododendron (R. Ponticum), from Pontus in Asia Minor ; it is sometimes 20 ft. high, but usually less than half that height. Its obovate-lanceolate leaves taper to the base, and its large, very open bell- shaped corolla is purple, opening in early spring. This is the common rhododendron of European gardens, and, though not generally hardy in our northern states, sometimes suc- ceeds if kept as a low bush and given a slight protection, without which its flower-buds will be winter-killed. Its chief use in this country is to furnish stocks upon which to graft har- dier kinds, as it grows readily from seeds. In Europe it has produced a number of vari- eties, some of which are hardier than the spe- cies. The tree rhododendron (R. arboreum) is a noble species from Nepaul, and still more tender than the Pontic ; the dark green leaves