Gums, Resins, 



226 



[Sept. 1906. 



Is the climate unfavourable ?— persisted the planter. 



Mr. Wright :— When I said that you had, in some parts a heavy rainfall at 

 high elevations which might be undesirable, I had in mind the vegetation on, and the 

 damp climate at, Hinidumkande ; the hill is only, if I remember correctly, a little 

 over 2,200 feet at its highest point. On the lower part of that hill, and the district 

 around it, the vegetation is very similar to what one finds in the Ratnapura distrct. 

 But as soon as you get 2,000 feet up the hill the arborescent vegetation is com- 

 pletely changed ; instead of the stalwart lofty trees of Valeria, Diospyros, 

 Dipterocarpus, Palaquium and Canarium species so common in the lower part, 

 you find the tree forms all stunted in growth, the foliage is poorly developed and 

 theTtrees are all covered with mosses, lichens, liverworts and even saprophytic 

 fungi. The change in the whole type of the vegetation is remarkable and the air 

 is damp and cold throughout a gieat part of the year. I do not for a moment 

 say that Hevea braxit tenuis would not grow, even at the top of Hinidumkande, but 

 the trees in such a climate would not mature as quickly as under more favourable 

 conditions. 



Is it the elevation or the rainfall ? 



Mr. Wright :— The rainfall is, perhaps, the more important factor. On 

 Passara Group Estate, Passara, with a relatively small rainfall, but at an elevation 

 of 2.600 feet, Mr. Stewart Taylor has obtained over 2 lb. of rubber per tree for 1905. 

 Again, many places in South India, though over 3,000 feet above sea-level, but with a 

 meagre rainfall, grow Pax*a rubber satisfactorily. An estate at an high elevation 

 with a low rainfall is very often more suitable than one at a similar elevation with a 

 heavy rainfall ; for instance, I should prefer Passara to the top of Hinidumkande. 

 A high rainfall at a high elevation is bad for Para Rubber. 



TREES WITHOUT LATEX. 



But is it correct that several trees at high elevations give very watery latex 

 and some none at all ? — queried another. 



Mr. Wright :— Yes, occasionally. 



What is the reason for such behaviour ; it surely cannot be general ? 



Mr. Wright: — You must make up your mind to expect great variations in 

 the nature and yield of latex from trees at all elevations, for the simple reason that 

 the laticiferous system, from which the milk is obtained, is not a vital part of the 

 tree. There is, of course, a general constancy and the majority of the trees of 

 Hevea brasiliensis possess latex throughout their lives ; but in some cases the trees 

 do not yield normal latex during certain periods, though subsequently they contain 

 this mixture in large quantities. Generally speaking, one may say that there is less 

 constancy in parts of the plant which are not of vital importance, than in those 

 upon which the continuity of the tree's life depends ; for instance, the peculiar cells 

 which are of vital importance and conduct and store food materials from the leaves 

 — phloem tubes and companion cells— are much more constant in the cortex of Hevea 

 brasiliensis than are the non-vital latex tubes. There is no need to get alarmed at 

 the fact that the latex is occasionally almost absent or possesses a low percentage of 

 rubber globules ; it is a natual variation which must be expected, considering the 

 non-vital functions of the latex and the hundreds of thousands of trees there are of 

 the same species— already there are planted in Ceylon about 20,000,000 Para rubber 

 trees, I understand. 



SELECTION OF SEED PARENTS. 



A third planter wished to know, What should be done to such trees. Should 

 seeds be used from such trees for planting ? 



