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AFRICA 



orchard trees in winter. There may be a bushy and 

 woody undergrowth, but generally the stony ground is 

 bare under and between the scattered trees. Meagre 

 steppes of dry and wiry bunch-grass alternate with 

 knee-high scrub, now open, now fairly close. The 

 thornbush vegetation of this region may be compared 

 to that of the sertao in the north-eastern part of the 

 Brazilian highlands. Extensive tracts among the wood- 

 and scrub-lands are covered with peculiar grass formations 



(TOiTlii 



Fig. 83. Floating Blocks of Sudd. 



which suggest meagre and patchy cornfields on a stony 

 soil, and constitute a specific feature of those regions. 



The lower portion of the district, in the immediate 

 vicinity of the Nile and under its beneficial influence, 

 shows already something of the luxuriance of grass of 

 the savana. The river flows between banks adorned 

 with groves of palms and other tall trees ; but behind 

 that fringe and occasional strips of savana, commence the 

 leafless, thorny scrub and woodland. The river forms 

 vast swamps bristling with tall reeds, papyri, sedges, 



