3o6 



ZONES AND REGIONS 



[Pt. Ill, Sect. 



thickness as occur in dry tropical districts. Tlicy are, on the contrary, mon 

 frequently quite smooth, or marked b\- shallow longitudinal and transvers' 



fissures. Indeed, the forma 

 tion of cork is often si 

 poor that moderately thic' 

 stems are green owing to th 

 chlorophyll of the cortics 

 layers being visible throug 

 it. It is possible that thephc 

 nomenon of cauliflory, whic 

 will be described further oi 

 is connected with the feeb! 

 development of bark. 



Rarely in the forest hf 

 one an opportunitj' of gair 

 ing an insight into the pre: 

 cise arrangement of tV 

 branches, for to achieve th' 

 the tree must be felle 

 In this respect again tl 

 Buitenzorg garden giv 

 ample opportunity for stud 

 although it should alwa; 

 be remembered that, besid 

 trees of the rain-forest, 

 also contains trees of d 

 ciduous forest, of littoi 

 forest, and even of savanna| 

 The very striking forms I" 

 umbrella-like trees are qui! 

 exceptional in the evergrej 

 \irgin forest — and even th| 

 they are usuallj' giants J 

 the forest, whose crow; 

 tower above the gene;l 

 leaf-canop\' — whilst the sljl 

 more striking forms of t|; 

 trees with their branches !i 

 tiers seem to be entin.' 

 absent from them. Suii 

 forms of trees are far more characteristic of well-lighted, deciduous, mc 

 or less xerophilous forest, of savannah, and of the highest forest regi 

 in the mountains, in short, of a drv climate. The crowns of the tm 



Fig. 144. Schizolobium excelsiim. 

 by Treub. 



.\fter a photograph ■ 



