26 PHENOMENA OF VEGETATION. 



ture must have beeu absorbed by the leaves, I may remark that this 

 appears to me to be a non-sequitur ; aod the burden of proof rests on 

 those by whom it is advanced. 



In regard to the general opinion that moisture is absorbed by the 

 leaves of trees I may state that I believe this to be the case where 

 leaves are covered more or less densly with hairs, which are highly 

 hygroscopic, and which appear to be organs well fitted for the accom- 

 plishment of such a function, and are often placed as if such were 

 their function in given conditions ; and furthex', that to some extent 

 moisture may have been absorbed by endosmose where a deposit of 

 what may be called a secretion on the surface of the leaf gives some- 

 thing like an indication of this having occurred, but that the effect of 

 this must be small. 



I have no testimony to the alleged absorption of moisture to an 

 appreciable extent by leaves having been observed ; and on the other 

 hand I have testimony on which I can rely that in South Africa there 

 are fig trees growing on rocks, over which the roots spread like 

 solidified molten lava or rosin, dipping down into every crevice and 

 spreading onward to the earth beyond ; and in the absence of evidence 

 of extensive absorption by leaves I consider it more probable that the 

 moisture is absorbed by such roots than by the leaves of the tree, 

 and the conclusion justified in such cases suggests the conclusion that 

 so may it be in others. 



Sect. II. — On the Frodicdion of Water by Plants, 



Amongst trees brought under my consideration in Africa by the 

 late Mr James Chapman — a man of cai'eful observation who travelled 

 extensively throughout the whole region from Walfish Bay to the 

 Victoria Falls of the Zambesi and thither from Natal, traversing in 

 various directions the country intermediate between the region thus 

 indicated and Table Bay at the Cape of Good Hope — was the Kusch6, 

 a large tree with a smooth dark grey-coloured bark and dark-coloured 

 oblong leaves, in the heart of the trunk of many of which is found a 

 large reservoir of water. From the description given to me, the tree 

 appeared to be the Millettia Caffra, known elsewhere in South Africa 

 as the Oomzambeete, or Kaffir Iron wood. 



Mr Chapman first saw this tree when he and his companions were 

 suffering from thirst. Observing one of his native servants placing 

 forked boughs against a tree and preparing to climb, he asked what 

 he was going to do. " Look for water," was the reply. The man 



