Page:Encyclopædia Britannica, Ninth Edition, v. 2.djvu/760

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694
ASIA
[botany.

be named the babool, Acacia ; toon, Cedrela ; and sissoo, Dalbergia. The only timber in ordinary use obtained from the Himalaya proper is the Deodar, Cedrus, not distinct from the cedar of Lebanon. Besides these are the sandal- wood, Santahim, of Southern India, and many sorts of bamboo found in all parts of the country. The chinchona has recently been introduced with complete success ; and the mahogany of America reaches a large size, and gives

promise of being grown for use as timber.

87. The flora of the rainless region of South-western Asia is continuous with the desert flora of Northern and Eastern Africa, and extends from the coast of Senegal to the meridian of 75 E., or from the great African desert to the border of the rainless tract along the Indus and the southern parts of the Punjab. It includes the peninsula of Arabia, the shores of the Persian Gulf, South Persia, and Afghani stan, and Baluchistan. On the west its limit is in the Cape de Verde Islands, and it is partially represented in Abyssinia.

88. The more common plants in the most characteristic part of this region in Southern Arabia are Capparidece, Fupkorbiacece, and a few Leguminosce, a Reseda and Dip- terygium ; palms, Polygonacece, ferns, and other crypto gams, are rare. The number of families relative to the area is very small, and the number of genera and species equally restricted, in very many cases a single species being the only representative of an order. The aspect of the vege tation is very peculiar, and is commonly determined by the predominance of some four or five species, the rest being either local or sparingly scattered over the area. The absence of the ordinary bright green colours of vegetation is another peculiarity of this flora, almost all the plants having glaucous or whitened stems. Foliage is reduced to a minimum, the moisture of the plant being stored up in massive or fleshy steins against the long-continued drought. Aridity has favoured the production of spines as a defence from external attack, sharp thorns are frequent, and asperi ties of various sorts predominate. Many species produce gums and resins, their stems being encrusted with the exudations, and pungency and aromatic odour is an almost universal quality of the plants of desert regions.

89. The cultivated plants of Arabia are much the same as those of Northern India wheat, barley, and the common Sorghum, with dates and lemons, cotton and indigo. To these must be added coffee, which is restricted to the slopes of the western hills. Among the more mountainous regions of the south-western part of Arabia, known as Arabia Felix, the summits of which rise to 6000 or 7000 feet, the rain fall is sufficient to develop a more luxuriant vegetation, and the valleys have a flora like that of similarly situated parts of southern Persia, and the less elevated parts of Afghanistan and Baluchistan, partaking of the characters of that of the hotter Mediterranean region. In these coun tries aromatic shrubs are abundant. Trees are rare, and almost restricted to Pistacia, Celtis, and Dodoncea, with poplars, and the date palm. Prickly forms of Statice and Astragalus cover the dry hills. In the spring there is an abundant herbaceous vegetation, including many bulbous plants, with genera, if not species, identical with those of the Syrian region, some of which extend to the Himalaya.

90. The flora of the northern part of Afghanistan ap proximates to that of the contiguous western Himalaya. Qucrcus Ilex, the evergreen oak of Southern Europe, is found in forests as far east as the Sutlej, accompanied with other European forms. In the higher parts of Afghanistan and Persia Boraginece and thistles abound ; gigantic Umbelliferce, such as Ferula, Galbanum, Dorema, Bubon, Peuccdanum, Pranrjos, and others, also characterise the same districts, and some of them extend into Tibet.

91. The flora of Asia Minor and Northern Persia differs Persia but little from that of the southern parts of Europe. The an . d Asi3 mountains are clothed, where the fall of rain is abundant, M with forests of Quercus, Fagus, Ulmus, Acer, Carpinus, and Corylus, and various Goniferce. Of these the only genus that is not found on the Himalaya is Fagus. Fruit trees of the plum tribe abound. The cultivated plants are those of Southern Europe.

92. The vegetation of the Malayan Islands is for the most part that of the wetter and hotter region of India; but the greater uniformity of the temperature and humidity leads to the predominance of certain tropical forms not so con spicuous in India, while the proximity of the Australian continent has permitted the partial diffusion of Australian types which are not seen in India. The liquidambar and nutmeg may be noticed among the former ; the first is one of the most conspicuous trees in Java, on the mountains of the eastern part of which the casuarina, one of the characteristic forms of Australia, is also abundant. Rhododendrons occur in Borneo and Sumatra, descending to the level of the sea. On the mountains of Java there appears to be no truly alpine flora ; Saxifraga is not found. In Borneo some of the temperate forms of Australia appear on the higher mountains. On the other islands similar characteristics are to be observed, Australian genera extending to the Philippines, and even to Southern China.

93. The analysis of the Hong Kong flora by Mr Bentham indicates that about three-fifths of the species are common to the Indian region, and nearly all the remainder are either Chinese or local forms. The number of species common to Southern China, Japan, and Northern Asia is small. The cultivated plants of China are, with a few exceptions, the same as those of India. South China, therefore, seems, botanically, hardly distinct from the great Indian region, into which many Chinese forms penetrate, as before no ticed. The flora of North China, which is akin to that of Japan, shows manifest relation to that of the neighbouring American continent, from which many temperate forms extend, reaching to the Himalaya, almost as far as Kashmir. Very little is known of the plants of the interior of Northern China, but it seems probable that a complete botanical connection is established between it and the temperate region of the Himalaya.

94. The vegetation of the dry region of Central Asia is remarkable for the great relative number of Chcnopodiaccce, Salicornia and other salt plants being common ; Polygonacece also are abundant ; leafless forms being of frequent occurrence, which gives the vegetation a very remarkable aspect. Peculiar forms of Leguminosce also prevail, and these, with many of the other plants of the southern and drier regions of Siberia, or of the colder regions of the desert tracts of Persia and Afghanistan, extend into Tibet, Avhere the extreme drought and the hot (nearly vertical) sun combine to produce a summer climate not greatly differing from that of the plains of Central Asia.

95. The zoological provinces of Asia correspond very closely with the botanical. The northern portion of Asia,

as far south as the Himalaya, is not zoologically distinct from Europe, and these two areas, with the strip of Africa north of the Atlas, constitute the Palaearctic region of Dr Sclater, whose zoological primary divisions of the earth have met with the general approval of naturalists. The south-eastern portion of Asia, with the adjacent islands of Sumatra, Java, Borneo, and the Philippines, form his Indian region. The extreme south-west part of the continent constitutes a separate zoological district, comprising Arabia, Palestine, and Southern Persia, and reaching, like the hot desert botanical tract, to Baluchistan and Siudh ; it belongs

to what Dr Sclater calls the Ethiopian region, which extends over Africa, south of the Atlas. The Celebes,