Rhododendron, a widely-diffused genus of shrubs and trees belonging to the heath tribe, with broad evergreen leathery leaves, and showy clusters of funnel-shaped or sub-campanulate, five-lobed, slightly mono-symmetric flowers, with ten stamens, generally declinate and dehiscing by pores. The genus is not separable from Azalea (q.v.). Most of the species are Indian, where some grow as epiphytes, as does also R. Brookeanum, of Sarawak. R. nivale grows at an altitude of 17,000 feet in the Himalayas; R. lapponicum on the shores of Davis Strait; R.ponticum, the honey of which is said to be poisonous, the commonest species in our gardens, is hardy and grows from self-sown seed in England; and R. catawbiense and others are natives of North America. Numerous hybrids have been raised in our nursery-gardens, and the flowers vary immensely in size, shape, spots, and in shades of white, red, and lilac.