82 



(although occasional showers and storms occur) is more pronounced 

 and the rainfall less equable than the driest months in Malaya. 

 Thus, the latex during this period in Brazil would contain the mini- 

 mum quantity of water and in the more rarified air, or, air containing 

 less water-vapour tlian in the rainy months, there would be less 

 tendency for latex coalescing too rapidly through atmospheric condi- 

 tions. 



5. The more material advantage, however, lies in the circumstance 

 that trees in tropical * countries conform to their natural periodicities 

 with most regularity where the dry season is sufficiently marked to 

 represent a true resting period. Here in Malaya, between mid-Janu- 

 ary and March on the western coast of the Peninsula — the season of 

 rice harvest — there occurs a short dry season when most of the deci- 

 duous trees shed their leaves and produce flowers. It is so with Hevea 

 braziliensis when the conditions are normal, but when, after heavy 

 rains from September to mid-January the rains still continue, then the 

 rubber trees may not, or only partially defoliate and the floral 

 periodicity may be scant or suppressed. The flowers too, through 

 heavy rains may be poorly pollinated only, and such trees, whether 

 partially defoliated or lightly pollinated, may perform their foliar 

 and floral function during the following August or September t thus 

 providing what is called the Spring crop of seeds, but the result is an 

 irregular and uncertain crop of latex ; as a matter of fact, a wet season 

 at the time of year under review is represented by the trees in every 

 physiological phase common to the species at diff"erent periods instead 

 •of the real season (February). I believe every planter is aware that 

 there is a fall off in the yield of latex at the time of trees wintering, 

 and the diversity of yield in the following tabulated statements will 

 be more apparent when it is reflected that every gradation of differ- 

 ence may have been exhibited by the trees at the time of tapping. 



6. In table l the diversity of yield within the same group of 200 

 Irees during a period of 5 years is shown. The diversity of resulting 

 rubber is more variable than the yield of latex. 



* In all countries when the dry season is not an absolute drought. 



t It is so with other trees. 



J Reduced to 25 lappings the result would be much less. favourable. 



