Page:The New International Encyclopædia 1st ed. v. 17.djvu/130

EHODODENDRON". 110 EHODOPHYCE^. similar species with narrower and more pointed leaves, of the same color on both sides, is a native of Western Asia, and apparently also of Southern Spain. Rhododendron catawbieiise, a native of the southern Alleghanies, with large pur])le flowers, and Rhododendron arhoreum, a native of Nepal, with very dense heads of large scarlet ilowers and leaves 12 to 18 inches long, attaining a height of 30 to 40 feet in its native nnoDODENDRON (Rbododendrou ponticum). country, are tine and well-kno^vn species; Rho- dodendron Califomieinn and Rhododendron ma- crophi/llmn are among the most conspicuous spe- cies of the Pacific Coast region, jlost of the extremely numerous varieties common in gardens and shrubberies have been produced from them. In many if not most of the hybrids, Rhododendron. Vataicbirnse enters, and in a list published in 1871. 250 named hybrids of this species are men- tioned. Since that time the number has un- doubtedly greatly increased. Many splendid species of Rhododendron have been discovered in the Himalaya, the Khasia Hills, and other mountainous parts of India, by Hooker and others; and some of them have been introduced into cultivation. Rhododendron grande has very beautiful flowers 4Vo inches in diameter. Rhododendron Maddcni. Rhododendron Griffithianum, Rhododendron Edncirorthii, and others have white flowers. Rhododendron Dal- housiw is remarkable as an ei)iphyte. growing on magnolias, laurels, and oaks. It is a .slender shrub, bearing from 3 to 6 white lemon-scented terminal bells. 4^^ inches long. Rhododendron 'Xuttullii has fragrant white flowers, said to be larger than those of any other species. All these belong to the Himalayas. In more southern lati- tudes, as on the Xeilgherrs- Hills and on the mountains of Ceylon, Rhododendron harhatum prevails as a timber tree, a blaze of crimson ■wben in flower. Rhododendron Keysii and Rho- dodendron cinnuharinum, natives of Northern India, have flowers with nearly tubular corollas. Rhododendron ferrugineum and Rhododendron hirsuium are small Alpine shrubs from 1 to 3 feet in height with umbellate clusters of carmine- colored flowers among the finest ornaments of alpine scenery. They are called alpvnrone (al- pine rose) by the Germans, and ai'c not easily cultivated in gardens. The flora of tlu- Himalaya contains a number of similar small species. Rhododendron selosum, a dwarf shrub with strongly scented leaves, clothes the mountains in Eastern Nepal at an elevation of 12.000 ftvt and upward, with a green mantle, brilliant with flowers in summer. Rhododeiulron nicale is the most alpine of woody plants, spreading its small woody branches close to the ground, at an eleva- tion of 17,000 feet in Sikkim. Rhododendron lapponictim, a procumbent shrub, with small . flowers, grows as far north as human settlements have reached in Europe and Asia. An oil ob- tained from the buds of Rhododendron ferrugine- um and Rhododendron hirsutum have been used by the inhabitants of the Alps imder the name olio di marmotta, as a remedy for various ail- ments. The flowers of Rhododendron arhoreum are .said to be eaten in India, and Europeans make a jelly of them. The wood of some of the larger species is white, hard, and close-grained, and has been recommended as a possible substi- tute for boxwood. Rhododendrons are not of diflicult culture, a soil containing plenty of leaf mold and protection from drought and winter scalding being the prime necessities for growing the hardier species in shrubberies and parks. See Colored Plate of Azaleas and Riiododendkons. RHODONITE (from Gk. p6iov,rhodon, rose). A mineral manganese silicate that crystallizes in the triclinie system, has a vitreous lustre, and is usiuilly red. although sometimes green or yel- low. It occurs frequently in association with iron and zinc ores, and is found in Sweden, the Harz. the Urals, and in the United States at various localities in Massachusetts, and in Sussex County, N. .J., where part of the manganese is replaced by zinc, giving rise to a variety known as foirlerite. The massive varieties of this min- eral, especially those found in the Ekaterinbiirg District in the Urals, are used for ornamental purposes, as for table tops, etc., while varieties from other places are used to a limited extent as gems. RHODOPHYCE.a; (Neo-Lat. nom. pi., from Gk. poihr, rliridon, rose,-}- (puKoc, phj/kos. seaweed). The red alg;c. The most beautiful of the four great groups of algte. Some are very complex in structure, but in general they show less vegeta- tive difTerentiation than do the brown algae ( Ph.Tophyeea'. q.v.). Their peculiarities lie chiefly in a highly developed method of sexual reju'oduction. resulting in a complex fruit (cysto- carp). which contains the carpospores. (Figs. 1. 2.) The male cells (spermatia) are non-motile, and fuse with a thread-like female receptive organ ( trichogyne ) . There is also a form of asexual re- production generally of four special spores (tet- raspores). (Fig. 1.) Most Rhodophycefe are red or reddish brovn, a color due to a peculiar pigment (phycoerythrin) which obscures the green pig- ment ( chlorophyll ) . The form of the body ranges from minute fila- ments of great delicacv' to broad membranes and thick cartilaginous fronds. Some of the mem- branous forms are several feet long (Delesseria), and may be diflerentiated into a stem and leaf-like oiit-growths. Others form filamentous branching tufts (Callithamnion, Dasya). Some groups bear