23 



It need not be pointed out that with Hevea, a careful 

 selection of seed is important. Brief attention may be 

 drawn to the great variability of Hevea, for important 

 differences are to be found between the trees. Variations 

 are frequently found in the form of the leaves, in 

 the manner of growth and also with regard to other 

 important characteristics. With some trees, the latex 

 flows all day, with the majority it ceases towards the 

 afternoon. Again, the characteristics do not always 

 remain constant throughout the whole life of the same 

 tree ; Mr. RIDLEY showed me, in the Botanical Garden at 

 Singapore, a tree which for several years had given a 

 bright yellow latex that had become modified to a cream 

 colour at the time of my visit. 



Besides such unusual irregularities, other deviations 

 occur which are, to some degree, hereditary and similar 

 to those which are to be found in other plants. 



Fasciated trees form an example of this nature. In 

 these trees the branches and upper part of the trunk 

 show a twisted manner of growth, forming somewhat of 

 a girdle round the tree. It appears to me that the yellow 

 and variegated plants which are not infrequently to be 

 met with in nurseries belong to the same category. 

 This yellow colour is often attributed to another cause, 

 lack of lime or iron (chlorosis) or of some plant food 

 in the soil. These yellow leaved plants are however to 

 be considered as hereditary variations which retain the 

 characteristic of deviation from type in more or less 

 strong proportion. 



It is not difficult to discover one of these yellow 

 leaved trees on a plantation ; they do not grow as 

 quickly as the normal plant, and they should be removed 



