40 SOUTH-WESTERN ASIA 



blossoms are among the more beautiful plants of the Mediterranean countries; 

 their leaves being either leathery and brilliant, or sticky from resinous secretions, 

 or else closely haired and consequently softer. The peculiar character of the hard- 

 leaved plants is distinctly shown in one of the spurge-laurels {Daphne gnidium), as 

 well as in an asparagus (Asparagus acutifolius) with its needle-shaped evergreen 

 leaves, and also in the tree-heather (Erica arborea), distinguished by its almost 

 tree-like mode of growth. In spots less densely covered with shrubs than else- 

 where, bulbous plants grow abundantly, in association with grasses, hard-leaved 

 evergreen perennials, and short-lived spring annuals which die soon after ripening 

 their seed. Poplars, ash, and other deciduous trees, unknown among the ever- 

 green woods, make their appearance near water and in damp soils. Forests of 

 northern trees, such as horse-chestnut, do not exist in the countries round 

 the coasts, but are restricted to the mountainous tracts, which have quite a different 



climate. 



The Mediterranean region consists in a great degree, if not in the greatest 

 degree, of deserts, whose origin is, of course, primarily due to a small annual 

 rainfall. In deserts, indeed, vegetation depends not so much on rain as on 

 warmth and the dryness of the air in summer, when these are at their maximum, 

 the life of desert-plants being more or less quiescent. 



Within the Mediterranean region is included the desert-tract crossing North 

 Africa, Arabia, southern Persia, and Baluchistan, throughout which the winter 

 climate is generally mild ; only the more northerly districts being visited by slight 

 frost and rapidly melting snow. The summer temperature is one of the hottest 

 known, rising in July over the greater part of the area to 96" or even higher. 

 The vegetation is of the same type as that of the Sahara. Rocky table- 

 lands, sandy valleys, hilly or flat stony plains, undulating expanses of sand, and 

 broad basins of clay lands are the leading physical features. Yet the desert is 

 by no means completely devoid of plants : its stony table-lands are the poorest in 

 vegetation, their only vegetable life being a few small thorny bushes. Less barren 

 are the sandy valleys and especially the banks of the (for the most part) dry water- 

 courses. The oases, which are the deepest valleys and the best-watered parts, 

 afford a sharp contrast to the rest of the tract, being abundantly clothed with trees 

 and plants. The distribution of desert-plants is much more dependent on under- 

 ground waters than on casual showers. In all deserts there is, however, probably a 

 --hurt-lived flora due to the brief rainfall in spring. Called to life by the moisture, 

 there shoot up a number of plants, which as a rule die at the end of the rainy period, 

 leaving the recently green ground as barren as before. Many perennial desert- 

 plants bear leaves and blossoms only during the rainy period, not because their 

 deep-seated roots are watered by the moisture, but because the evaporation of 

 their sap is checked by the moisture in the atmosphere. 



Then- is. of course, a complete transition from a true desert to ordinary country, 

 and some of the tracts of intermediate type may be called semi-deserts. That 

 part of Arabia lying southward of the 20th degree of latitude may, for instance, 

 be ttrine.l a semi-desert, its fauna showing affinity in the main with that of Africa 

 south of the Sahara, with some admixture of forms characteristic of the Medi- 

 terranean region. Central Asia Minor, Armenia, Kurdistan, south-western Persia, 



