The noblest of the genus is that which is dedicated to Lady Dalhousie. It is an epiphyte, being always found growing, like the Orchids, among mosses and ferns, upon the trunks of large trees, especially oaks and magnolias, at an elevation of from seven to ten thousand feet. In this particular, in the fragrance of its noble white blossoms, in its slender habit, in the whorled arrangement of its branches, and in the length of time during which it continues in flower in its native regions, viz., from April to July, it differs from all its fellows of the same genus that inhabit northern India. The flowers are four inches in length and four in diameter, with a broad trumpet lip. Their colour is pure white, assuming a delicate rosy tinge as they become old, and sometimes becoming spotted with orange. They have an odour which resembles that of the lemon. Of this and the following species Dr Hooker writes from Dorjiling, seven thousand feet above the sea:--"On the branches of the immense purple-flowered magnolia, (_M. Campbellii_,) and those of oaks and laurels, _Rhododendron Dalhousiæ_ grows epiphytally, a slender shrub bearing from three to six white lemon-scented bells, four and a half inches long and so many broad, at the end of each branch. In the same woods the scarlet Rhododendron (_R. arboreum_) is very scarce, and is outvied by the great _R. argenteum_, which grows as a tree, forty feet high, with magnificent leaves twelve to fifteen inches long, deep green wrinkled above and silvery below, while the flowers are as large as those of _R. Dalhousiæ_ and grow more in a cluster. I know nothing of the kind that exceeds in beauty the flowering branch of _R. argenteum_, with its wide-spreading foliage and glorious mass of flowers."[222] The latter, which is nearly equal to _R. Dalhousiæ_ in the size of its blossoms, and perhaps superior to it in other respects, is another white-flowered species. It is, as described above, a tree with large massive leaves of a silvery tint beneath. When young, they are exquisitely beautiful, being encased in long flesh-coloured cones of large scales, of very ornamental appearance. The flowers are three inches long, forming a compact globose head. They secrete a large quantity of honey, which is said to be poisonous, as is also that of _R. Dalhousiæ_. The grandeur and beauty of the same genus are celebrated by Mr Low, as he saw the species growing in Borneo, where too their parasitic character struck him, as it had done Dr Hooker:--