Page:Encyclopædia Britannica, Ninth Edition, v. 2.djvu/759

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botany.]
ASIA
693

its greatest development in this part of Asia. The chief trees belong to the orders of Terebinthacece, Sapindacece, Meliacece, Chisiacece, Dipterocarpea?, Ternstrcemiaceoe, Legu- minosce, laurels, oaks, and figs, with Dilleniacece, Sapotaceae, and nutmegs. Bamboos and palms, with Pandanus and

Dracaena, are also abundant. A similar forest flora extends along the mountains of eastern India to the Himalaya, where it ascends to elevations varying from 6000 to 7000 feet on the east to 3000 or 4000 feet on the west.

80. The arboreous forms which least require the humid and equable heat of the more truly tropical and equatorial climates, and are best able to resist the high temperatures and excessive drought of the northern Indian hot months from April to June, are certain Leguminosoe, Bauhinia, Acacia, Butea, and Dalbergia, Bombax, Shorea, Nauclea, Lagerstrosmia, and Bignonia, a few bamboos and palms, with others which extend far beyond the tropic, and give a tropical aspect to the forest to the extreme northern border of the Indian plain.

81. Of the herbaceous vegetation of the more rainy regions maybe noted the Orchidece, Orontiacece, Scitaminece, with ferns and other Cryptogams, besides Graminece and Cyperacece. Among these some forms, as among the trees, extend much beyond the tropic and ascend into the tem perate zones on the mountains, of which may be mentioned Begonia, Osbeclda, various Cyrtandracece, Scitaminece, and a few epiphytical orchids.

82. Of the orders most largely developed in South India, and more sparingly elsewhere, may be named Aurantiacece, Dipterocarpecc, Balsamineae, Elenacece, Jasminece, and Cyrtandracece; but of these few contain as many as 100 peculiar Indian species. Nepenthes may be mentioned as a genus specially developed in the Malayan area, and extending from New Caledonia to Madagascar ; it is found as far north as the Khasiya hills, and in Ceylon, but does not appear on the Himalaya or in the peninsula of India. The Balsamineae may be named as being rare in the eastern region and very abundant in the peninsula. A distinct connection between the flora of the peninsula and Ceylon, and that of eastern tropical Africa is observable not only in the great similarity of many of the more truly tropical forms, and the identity of families and genera found in both regions, but in a more remarkable manner in the like ness of the mountain flora of this part of Africa to that of the peninsula, in which several species occur believed to be identical with Abyssinian forms. This connection is further established by the absence from both areas of oaks, conifers, and cycads, which, as regards the two first families, is a remarkable feature of the flora of the penin sula and Ceylon, as the mountains rise to elevations in which both of them are abundant to the north and east. With these facts it has to be noticed that many of the principal forms of the eastern flora are absent or compara tively rare in the peninsula and Ceylon.

83. The general physiognomy of the Indian flora is mainly determined by the conditions of humidity of climate. The impenetrable shady forests of the Malay peninsula and Eastern Bengal, of the west coast of the Indian peninsula, and of Ceylon, offer a strong contrast with the more loosely- timbered districts of the drier regions of Central India and the North-western Himalaya. There are no plains covered with forest as in tropical America, the low lands of India being either highly cultivated and adorned with planted wood, or, where cut off from rain, nearly complete desert.

84. The higher mountains rise abruptly from the plains; on their slopes, clothed below almost exclusively with the more tropical forms, a vegetation of a warm temperate character, chiefly evergreen, soon begins to prevail, com prising Magnoliaccce, Ternstrcer.it acea , sub-tropical JRosaccce, rhododendron, oak, Ilex, Symjilocos, Laurinecc, Pinus longi- folia, with mountain forms of truly tropical orders, palms, Pandanus, Musa, Vitis, Vernonia, and many others. On the east the vegetation of the Himalaya is most abundant Eastern, and varied. The forest extends, with great luxuriance, to an elevation of 12,000 feet, above which the sub-alpine region may be said to begin, in which rhododendron scrub often covers the ground up to 13,000 or 14,000 feet. Only one pine is found below 8000 feet, above which several other Conifcrce occur. Plantains, tree-ferns, bamboos, several Calami, and other palms, and Pandanus, are abundant at the lower levels. Between 4000 and 8000 feet epiphytal orchids are very frequent, and reach even to 10,000 feet. Vegetation ascends on the drier and less snowy mountain slopes of Tibet to above 18,000 feet. On the west, with Western, the drier climate, the forest is less luxuriant and dense, and the hill sides and the valleys better cultivated. The warm mountain slopes are covered with Pinus longifolia, or with oaks and rhododendron, and the forest is not com monly dense below 8000 feet, excepting in some of the more secluded valleys at a low elevation. From 8000 to 12,000 feet, a thick forest of deciduous trees is almost universal, above which a sub-alpine region is reached, and vegetation as on the east continues up to 18,000 feet or more. The more tropical forms of the east, such as the tree-ferns, do not reach west of Nepaul. The cedar or Deodar is hardly indigenous east of the sources of the Ganges, and at about the same point the forms of the west begin to be more abundant, increasing in number as we advance towards Afghanistan.

85. The cultivated plants of the Indian region include Cultivated wheat, barley, rice, and maize ; various millets, Sorghum, plants. Penicillaria, Panicum, and Eleusine ; many pulses, peas, and beans ; mustard and rape ; ginger and turmeric ; pepper and capsicum; several Cucurbitacece ; tobacco, Sesamum. poppy, Crotolaria, and Cannabis; cotton, indigo, and sugar; coffee and tea; oranges, lemons of many sorts; pomegranate, mango, figs, peaches, vines, and plantains. The more com mon palms are Cocos, Phoenix, and Borassus, supplying cocoa-nut and toddy. Indian agriculture combines the harvests of the tropical and temperate zones. North of the tropic fie winter cold is sufficient to admit of the cultiva tion of almost all the cereals and vegetables of Europe, wheat being sown in November and reaped early in April. In this same region the summer heat and rain provide a thoroughly tropical climate, in which rice and other tropical cereals are freely raised, being as a rule sown early in July, and reaped in September or October. In southern India, and the other parts of Asia and of the islands having a similar climate, the difference of the winter and summer half years is not sufficient to admit of the proper cultiva tion of wheat or barley. The other cereals may be seen occasionally, where artificial irrigation is practised, in all stages of progress at all seasons of the year, though the operations of agriculture are, as a general rule, limited to the rainy months, when alone is the requisite supply of water commonly forthcoming.

86. The trees of India producing economically useful timber are comparatively few, owing to the want of durability of the wood, in the extremely hot and moist climate.

The teak, Tectona grandis, supplies the finest timber. It is found in greatest perfection in the forests of the west coasts of Burmah and the Indian peninsula, where the rain fall is heaviest, growing to a height of 100 or 150 feet, mixed with other trees and bamboos. The sal, Shorea robusta, a very durable wood, is most abundant along the skirts of the Himalaya from Assam to the Punjab, and is found in Central India, to which the teak also extends. The sal grows to a large size, and is more gregarious than

the teak. Of other useful woods found in the plains may