444 



expected with a climate so humid and with an equable rainfall the 

 normal condition is but seldom obtained. In this respect the year 

 of Report (1905) is the best example. During February and March 

 only 300 seeds were collected and as these months represent the 

 winter or dormant period it will be inferred, as did occur, there was 

 a heavy leaf fall and a better than usual resting period so necessary 

 for a heavy or exhaustive autumn crop which ripens about six month's 

 after the flowers appear. The direct effect of a heavy rainfall or the 

 necessity of very little rain at the foliar periodicity is shown in the 

 following tables : — 



Rainfall. 



1904: December 9*98 

 1905 : January 5-28 

 1905 : February 579 



Total 21*05 



Fruit Crop. / 9°S- 



1905: August 60,050 Seeds 



September 86,600 do. 



October 37,000 do. 



Total 184,450 Seeds. 



Ramfall. 



1905 : December 9*46 



1906 : January 16-87 

 1906: February 5-80 



Total 32-13 



Fruit Crop. igo6. 



1906: August 12,175 Seeds 



September 64,900 do. 



Octcber 15,720 do. 



Total 92,795 Seeds. 



It must be remarked that the paucity of fruit crop is not the true 

 expression of the effects of climatic conditions on all the functions 

 of the trees and their variability or activity throughout the year, as 

 the fruit crop may be marred at the time of pollination by the 

 physical agency of heavy rain showers. 



No better instance of rain damage could be cited than in the case 

 of the durian {Durio zibethinus). In Malaya it is common know- 

 ledge that a heavy rain shower at the time of pollination seriously 

 affects the prospective crop and continuous rain utterly destroys it. 

 The durian, too, furnishes a good example of variability. Several 

 years may pass with only one flowering period and occasionally, as 

 during the current year, when a good crop was ripened last July and 

 August, profuse flowers were produced the following September, 

 nearly all of which in the vicinity of the Botanic Gardens were lost 

 through heavy rains. 



Hevea braziliensis is a monoecious tree, with male and female 

 flowers on the same panicle or rather compound cyme. The male 

 flowers are vastly more numerous than the female, which are borne 

 singly on the subterminal branchlet of each cyme branch. The 

 female flower opens first and remains attached to its pedicel. The 

 perianth withers on the fertilized ovary and eventually is pushed off 

 as the ovary grows. The male flowers are more numerous and 

 open after the females on the same panicle are withered. They fall 

 off completely from the pedicels after discharge of the pollen. The 

 flowers are all yellow, and very strongly and sweetly scented. 



