IN THE DESERT 



by the fleshy stems, whose rind does the work of building up the 

 tissues of the plant. The stems also store up water to be used in the 

 dry season, and prevent its evaporation from the succulent tissues 

 by the large amount of mucilage which they mix with it. Moreover, 

 the skin of the cactus is very thick, and often coated with a bluish 

 bloom of a waxy consistency. By these means the cacti defy the heat 

 of the sun and the drought, or at most they gradually become 

 slightly shrivelled. If segments of the lateral shoots break off and 

 fall to the ground they begin to take root. 



The peculiarity to be noted in so many tropical leaves, which 

 grow thicker in order to protect the inner tissues from the sun, and 

 the better to preserve the internal moisture, has reached its highest 

 development in the stems of the cacti. But other thick-leaved plants 

 inhabit the Sertao : namely, the Macambiras, a species of Bromelia, 

 whose rosettes often cover the ground far and wide. Their fibres are 

 used for making nets. There are species among the orchids also, 

 and many kinds of Euphorbia are found even in the dry areas, the 

 stems and stalks being thickened as in the cacti, while the leaves 

 disappear. The gardeners call all those plants which look as though 

 they had somehow been fattened succulent plants. 



But there is yet another means of avoiding the loss of moisture 

 during the dry season, and enduring the rainless months without 

 desiccation. Plants, of course, transpire mainly through their leaves, 

 whose broad surfaces favour evaporation, just as the water in a wide, 

 flat saucer will evaporate more quickly than the water in a deep 

 flask exposing but a small surface. In order to avoid losing all their 

 moisture through their foHage, many of the plants of dry areas cast 

 their leaves, as do our own trees in winter. It has been estimated 

 that in Ceylon there are roughly a hundred trees which cast their 

 foliage, for Ceylon too has dry areas in which it hardly ever rains. 

 In the deserts of Brazil, however, all the woods are more or less 

 leafless. When the rain falls in January all is green in an incredibly 

 short time. A traveller once related that he fell asleep in a bare, 

 ashen-grey wood, and when he woke in the morning he thought he 

 must have been bewitched, for he was surrounded by billows of 

 green foliage. Rain had fallen overnight. 



Wherever there is a lake or lagoon we see lush green banks even 

 in the dry season. Bananas with their emerald-green leaves grow in 

 such waterside meadows, and sometimes we may see a coconut- 

 palm that has strayed from its usual haunts: but as a rule the 

 only palm to be found is that child of the Sertao, the Carnauba, a 



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