September, 1911.] 



217 



Edible Products. 



The growth of stems and roots, if an 

 accurate enough record is kept, is found 

 never to be steady, and the true explan- 

 ation of its irregularity is probably ana- 

 logous to that just given for the greater 

 irregularity of the growth of the coco- 

 nut leaves. In the stems and roots, the 

 cells and tissues, having unequal in- 

 herent power to enlarge, as we know 

 they have, set up tensions, the accumu- 

 lation and release of which are expressed 

 by the observable irregularities of rate. 

 In roots there is also the opportunity for 

 tensions between cap and body, in spite 

 of the fact that the most rapid enlarge- 

 ment is often back of the cap. In the 

 coconut, the entire elongating region is 

 usually enclosed, and must inevitably 

 stretch with more or less of a jerk every 

 time the hold between the back cart of 

 the cap and the enclosed body is over- 

 come. 



The rate of growth is also consequently 

 a function of the weather. As an illus- 

 tration, a severe storm began October 31, 

 and the growth during the four day 

 interval following was slower in most 

 cases than it had been immediately 

 before. Again, there was some rain 

 February 5 and 6, and February 8 and 

 9 were stormy. Vibar's table shows a 

 slower growth during the four days, 

 February 4 to 8, than during the pre- 

 ceding three days. This is more clearly 

 brought in Table III, containing the 

 measurements of Lejano, of the youngest 

 leaves only of six trees. 



Table III. 

 Growth per diem of youngest leaves 

 during the periods ending on the dates 

 given. Beginning January 28 : — 



Tree. 



Jan. Feb. Feb. Feb. 

 31 2 7 9 



Feb. 



16 

 22 3 

 39- 

 23- 

 29-4 

 135 

 12- 

 25-3 

 16 '9 



I ... 30 7 32 2 26-5 15-5 



II .. 31 32-5 31-4 12- 



III ... 16 18-5 25- 9-5 

 Average ... 26-9 27* 727"6 16 3 



IV ... 14- 25' 17-8 8-5 

 V ... 19- 17-8 16 2 15 5 



VI ... 32- 33-2 29 4 20' 

 Average ... 213 25-3 211 147 



It has already been noted that Lejano's 

 trees are on very shallow soil, which 

 had become decidedly dry by the end of 

 January. The growth of his trees was 

 slower at the beginning of February 

 than during the preceding September ; 

 while the students whose trees grow 

 on deeper soil found the growth in 

 February more rapid than at anv 

 previous time. 



It will probably be a cause of surprise 

 to many, as it was at first to me, that a 

 few days of rainy weather have a 

 decided deterrent effect upon the 

 growth. Most plants growing in the 

 Philippines whether herbs, vines or 

 trees, and in whatever stage, show this 

 more markedly than does the coconut. 

 Several hundred species, records of the 

 growth of which are in my hands, have 

 shown this whenever the records were 

 so timed as to bring it out. 



The difference between the diurnal 

 and the nocturnal growth appeared as 

 conspicuously as possible in my San 

 Ramon work ; for not merely was there 

 frequently no growth at all during the 

 day, but there was sometimes an actual 

 shortening. Working here with adult 

 trees, and at a time when the water 

 supply for the root was ample, the 

 difference was still evident. It is shown 

 by Table IV, compiled from the tables 

 of Cevallos. 



Table IV. 



Growth of Leaves by Day and by Night. 



bold-faced type, 5 p.m. to 5 a.m. 



3 Trees. 





Leaf. 



i 



2 



3 



1 



2 



3 



1 



2 



3 



6 



... o-o 



10-3 



0-9 



0-2 



130 



0-8 



0-5 



185 



5-0 



1-4 





... 1-0 



22-0 



3-1 



11 



48-0 



1-2 



3'0 



47-9 



24-8 



5-6 



7 



... 06 



23-8 



2-0 



0'4 



14'4 



1-0 



1-0 



11-0 



7'0 



1-0 





... 2-4 



41-0 



6-2 



9 



41-6 



3-C 



3-2 



52-0 



18-0 



4-0 



8 



... o-o 



4-0 



1-5 



0'3 



11-0 



0-5 



0-9 



13-2 



2-1 



0-6 





... 0-5 



38 2 



5'0 



1*5 



24 



4-0 



2-0 



33-0 



37-9 



2-4 



9 



... 00 



6 



22 



0-6 



18'0 



1-3 



0-8 



7-2 



5-0 



16 





... m 



27 



4'5 



4-0 



54-0 



5'1 



1-0 



29-0 



32'0 



4-0 



All figures represent millimeters. The first column is growth in width ; other 

 wise, all are increment in length. 



The checking of the growth during 

 the day is obviously a function of the 

 decreased water supply of the crown of 

 the tiee. The same is true, at least in 

 large part, of the damage done by 

 drought. On the other hand the check- 

 28 



ing of growth by prolonged rainy 

 weather seems unintelligible, except as a 

 result of the checking of photosynthesis. 

 It is true that the temperature is usu- 

 ally lower during storms ; but it is like- 

 wise true that February is a colder 



