INDIA is a rich source of Dendrobium species. There are many species distributed in nature in various parts of the country, growing chiefly on trees in the forest jungles at various heights. Each will come into flower once a year and, taking all species into account, there will always be several in bloom each month. Many of them are very showy and attractive and have gained world-wide popularity for their ornamental value. Some of the species, Dendrobium aggregatum, Den. chrysotoxum, Den. dalhousieanum, Den. formosum, Den. nobile, Den. primulinum and Den. williamsoni, have served as parent plants in hybridization, and have contributed several hybrids of outstanding merit.

The distribution is so wide that there is a great variation in the principle characteristics of this genus. The species have more than one stem, some have pseudobulbs, a few have jointed, cane-like stems and others have a variety of forms and sizes. The foliage is strap-shape or ovate, or sometimes very narrow or grass-like, and it is either deciduous or persistent until the pseudobulbs perish. Flowers are produced singly, in clusters, or in short or long arching sprays.

The purpose of this article is to give a comprehensive list of valid Indian Dendrobium species with very brief descriptions, along with a note on the climate of the location in which they grow naturally in abundance.

The climate in the natural home of these Dendrobium species is worth attention in order to determine the cultural requirements. It will appear from observation of the habitat that in general, the species require heat and himidity during the active phase of vegetative growth, with moderate exposure to air and light in order to mature growth, followed by a cooler and decidedly drier period for rest during the winter months. The largest concentration of Dendrobium species is found in Assam, Khasia Hills, Manipur, Naga Hills and Cachar.

The climate in these regions is monsoon tropical with particularly heavy rainfall, averaging 190 to 212 cm on Shillong Plateau;275 to 300 cm in the Brahmaputra Valley, 300 to 375 cm in the Surma Valley;and over 375 cm maximum rainfall recorded in one year in Cachar. An average of over 1000 cm has been recorded in the southern slopes of the Khasia Hills. At Cherrapunji the annual average is 1150 cm and one year the world's heaviest precepitation was recorded, over 2000 cm. Mean temperatures ranges from 62 degree F in january to 84 degree F in july. During the greater part of the year the atmospheric humidity is near the saturation point. The wettest months are from june to september and the dry season ranges from the middle of October to the end of February.

Sikkim Himalaya and Darjeeling comprise another important zone where large numbers of dendrobiums are distributed in nature and create one of the richest botanical areas in India. This area is predominantly a mountanious area with Nepal in West and Assam Himalayas in the East, drained by the Tista River. This may be divided into three climatic zones: tropical(up to 1700 meters), temperature (from 1700 to 4300 meters) and alpine (4300 meters to the perpetual snow line at 5300 meters).

A large number of species are also found in the plains of West Bengal and the hilly regions of Bihar and Orissa. In West Bengal Dendrobium species are distributed in the hot humid regions. The overall climate of this state is monsoon tropical, with the annual rainfall averaging 190 cm (250 cm in East Sundarbans and 250 to 300 cm in the Himalayan foothills). The mean temperature ranges from 65 degree F to 85 degree F in May (the maximum in hot weather is from 110 degree to 115 degree F). Chota Nagpur in Bihar is rich in orchid species situated at altitudes ranging from 700 to 1200 meters with an annual rainfall of 125 to 150 cm. Some species are found in hilly regions of Orissa with an annual rainfall averaging from 100 to 150 cm and from an altitude of 500 to 1000 meters.

A considerable number of species are found in the Kumaon Hills, comprising Mainital, Almora, Garhwal and Tehri districts. The Kumaon Himalayas give rise to several sacred Indian rivers, including the Bhagirathi rising from the Gangotri Glacier, the Jamuna and the Aloknanda.

Central and Southern India contain a large number of Dendrobium species, some of which are very curious and interesting. Among the most important Dendrobium rich areas mention may be made of Konkan, Kanara, Malabar and the Nilgiri Hills. Konkan is the most important place in this regard, situated as it is in the coastal plain in West Bombay between the western Ghats and the Arabian Sea with an annual rainfall of over 250 cm and with seven dry months. Kanara is situated in south Bombay on the west edge of the Deccan plateau, and is crossed from the north to the south by the Western Ghats, with a narrow coastal strip on the Arabian Sea in the west and bounded on the northwest streams. The Deccan Plateau is a triangular tableland covering most of the peninsular part of India. It is enclosed at its apex in the south by the junction of the Eastern Ghats and the Western Ghats which spread out northeast and northwest respectively forming escarpments on the east and west. Malabar lies between the Western Ghats and the Malabar coast of the Arabian Sea. The annual rainfall of 200 to 300 cm occurs during July to September and increases to over 500 cm on the mountain slopes. The dry period on the Malabar Coast is only for three months.

Dendrobiums are also plentiful in the Nilgiri Hills, which is a steep plateau adjoining the South Deccan Plateau at the convergence of the Eastern and Western Ghats located in southwest Madras. The average height of these hills is 2200 meters, including several peaks over 2700 meters.

Some Dendrobium species are also reported from the Andaman and Nicobar Islands in the Eastern Bay of Bengal. This consists of hilly terrain, raising to 800 meters on Saddle Peak on North Andaman Island. The climate is monsoon tropical, characterized by a mean temperature of 85 degree F and heavy annual rainfall ranging from 225 cm to 325 cm, mostly during June through September.

LINKS-DENDROBIUM SPECIES LISTING