Edible Products, 



218 



[September, 1911. 



month than any from July to December, 

 and yet it shows the most rapid growth 

 except when dryness interferes. As a 

 matter of fact, our differences in 

 temperature from day to day, or from 

 month to month, are less than the usual 

 difference between day and night, and 

 the fact the night is cold does not 

 prevent rapid growth at that time. 



Regarding the relation between the 

 rate of growth and the age of the tree, 

 it can be laid down as a general rule 

 that from germination to maturity there 

 is a gradual increase in the rate of 

 growth of the most active leaves. The 

 younger the tree, the slower the growth. 

 This has been demonstrated on trees of 

 various sizes ; but as the exact ages of 

 the trees are not known, it is not worth 

 while to publish a tabulation of the 

 measurements. 



It has been emphasized, perhaps un- 

 necessarily since it is necessarily so, 

 that the measurements apply only to 

 the visible leaves. When we state that 

 the most rapid growth is shown by the 

 youngest visible leaf, it means that 

 when a leaf appears it is at near the 

 stage where the cure representing its 

 grand period would reach the highest 

 point. There are also present numerous 

 invisible leaves, the most of which are 

 very small and growing very slowly. 

 Dissection of a young tree, whose free 

 trunk was as yet only 50 cm. high, 

 showed the following leaves which had 

 not yet reached the light, but were 

 well enough formed to be separated 

 with a pocket knife and without the 

 use of a lens. These are numbered from 

 the largest to the smallest. 



Table V. 

 Length of Concealed Leaves. 



I ... ... 1-31 m. 



II ... ... 0-43 m. 



III ... ... 0'09 m. 



of which, 19 mm. sheath. 



IV ... ... 50' mm. 



V ... ... 34- mm. 



of which, 16 mm. sheath. 



VI ... ... 21- mm. 



VII ... ••• 15* mm. 



of which, 0*7 mm. sheath. 



VIII ... ... 13-mm.(?) 



IX ... ... 112 mm. 



X ... ... 8-7 mm. 



XI ... ... 7*1 mm. 



XII ... ... 5'5 mm. 



XIII and XIV separable, but too small 

 to measure accurately. 



The rate of growth at different ages 

 can be calculated approximately by the 

 differences in length. It is evident that 

 the growth in length is at first exceed- 



ingly slow, less even than 2 mm. a month, 

 and increases until the leaf reaches the 

 light. 



In our coconuts, the interval between 

 the appearance of successive leaves is 

 usually more than one month ; so that 

 fully eighteen months can be expected 

 to elapse before the smallest leaf-rudi- 

 ment recognizable with the naked eye 

 would grow into the light. Any condi- 

 tion which controls the rate of form- 

 ation of these leaf-rudiments must there- 

 fore have more or less influence on the 

 rate of the appearance of new leaves a 

 year and a half later, and on the crops 

 the tree can bear a year and a half later 

 still. And this influence is a direct one. 

 In the case of the coconut, as of any 

 other perennial, unfavourable condi- 

 tions, by lowering the general vitality of 

 the tree, have indirect effects, the dura- 

 tion of which is altogether indefinite. 



The fact that leaves succeed each 

 other at intervals of more than one 

 month indicates that our coconuts are 

 not in very good condition ; for at San 

 Ramon, until the drought became too 

 severe, the succession was considerably 

 more rapid. In consideration hereof 

 it may be anticipated that better situ- 

 ated coconuts will under favourable con- 

 ditions show a more rapid growth of the 

 leaves than any we have been able to 

 observe. 



At the time these coconuts came into 

 possession of the college the grove was 

 infested with cogon (lalang) where fire 

 had run through it, and grown up with 

 brush and small trees elsewhere. During 

 the following year it was not cleaned, 

 except immediately around the trees, 

 with a bolo. After a thorough cleaning 

 out it was ploughed shallowly during 

 the first week of last September; the 

 ploughing reached at the most a depth of 

 less than ten centimeters. As a result of 

 the lack of previous cultivation, and of 

 the shallowness of the soil, this plough- 

 ing cut many of the roots. This was of 

 course immediately in j urious to the trees. 

 The number of leaves on them was at 

 first from 21 to 27. During the succeed- 

 ing two months the majority of the 

 ploughed trees shed four leaves, while 

 neighbouring trees shed on the average 

 less than two leaves. There was also 

 an evident and immediate cheeking in 

 the rate of growth of the younger leaves, 

 from which the trees gradually re- 

 covered in the course of about three 

 months. After this interval the growth 

 became more rapid than it had been 

 before cultivation. 



In spite of the temporary set-back it 

 gives to trees hitherto neglected, there 

 is no reasonable doubt as to the value 



