Rhododendron — Rhododendron (from the Greek: rhodos, “rose”, and dendron, “tree”) is a genus of flowering plants in the family Ericaceae. It is a large genus with over 1000 species and most have showy flower displays. It includes the plants known to gardeners as azaleas.
The Rhododendron is an interesting genus characterized by shrubs and small to (rarely) large trees, the smallest species growing to 10-20 cm tall, and the largest, R. arboreum, reported to 50 m tall. The leaves are spirally arranged; leaf size can range from 1-2 cm to over 50 cm, exceptionally 100 cm in R. sinogrande. They may be either evergreen or deciduous. In some species the underside of the leaves are covered with scales (lepidote) or hairs (indumentum). Some of the best known species are noted for their many clusters of large flowers. There are alpine species with small flowers and small leaves, and tropical species such as subgenus Vireya that often grow as epiphytes.
Rhododendron is the national flower of Nepal. It is mostly found in Himalayan countries such as Nepal. It is a very widely distributed genus, occurring throughout most of the Northern Hemisphere except for dry areas, and extending into the Southern Hemisphere in southeastern Asia and northern Australasia. The highest species diversity is found in the Sino-Himalayan mountains from central Nepal and Sikkim east to Yunnan and Sichuan, with other significant areas of diversity in the mountains of Indo-China, Korea, Japan and Taiwan. In addition, there are a significant number of tropical rhododendron species from southeast Asia to northern Australia, with 55 known species in Borneo and 164 in New Guinea. Relatively fewer species occur in North America and Europe. Rhododendrons have not been found in South America or Africa.