Dendrobium-- (Swartz 1799) is a large tropical genus of orchid that consists of about 1200 species. This genus occurs in diverse habitats throughout Asia, the Philippines, Borneo, Australia, New Guinea and New Zealand. The species are either epiphytic, growing on a tree, or occasionally lithophytic, growing over a rock. They have adapted to a wide variety of habitats, from the high altitudes in the Himalayan mountains to lowland tropical forests and even to the dry climate of the Australian desert. The orchids in this genus develop large pseudobulbs, which unite into a long reedlike stem with a typical length of more than 30 cm. These are densily covered with short white hairs. The short, ovate leaves grow alternately over the whole length of the stems. The axillary flower buds develop into short flower stalks with one or two terminal flowers. The orchids grow quickly throughout summer, but take a long rest during winter. In the spring, new shoots are formed from the base of the main plant and the dormant buds come back into action. The blooming flowers are found on pseudobulbs formed in the previous year. Some species are in great demand by orchid lovers. This has resulted in numerous varieties and hybrids, such as the Dendrobium nobile varieties, which have greatly extended the range of colors of the orginal flower from the Himalayas.