234 



The Philippine Journal of Science 



illumination was not much less than at midday, but the temper- 

 ature was 4° or 5° lower. This experiment substantiates the 

 opinion previously reached that illumination in itself is practi- 

 cally without direct influence on the rate of growth ; but the same 

 experiment demonstrates that temperature has great influence 

 on growth, and suggests that an increase of 5°, say a change from 

 26° to 31°, is sufficient almost to double the growth rate. 



A considerable number of measurements of growth by centi- 

 meter zones were made in light and in darkness, using in all 

 cases plants which were among the most rapid in their growth. 

 The general result was that the plants in light had a considerably 

 longer growing region, and that the region of most rapid growth 

 was farther from the apex. A few illustrations will suffice to 

 make this clear. 



Table VI. — Growth in millimeters of centimeter zones. 



Centimeter zone. 



May 18-19. 

 College No. 88. 



May 9-10. 

 College No. 88. 



May 9-10. 

 College No. 331. 



May 18-19. 

 College No. 960. 



In light. 

 Dry 9. 



In dark- 

 ness. 

 Soil 2. 



In light. 

 Dry 1. 



In dark- 

 ness. 

 Soil 3. 



In light. 

 Dry 5. 



In dark- 

 ness. 

 Soil 1. 



In light. 

 Soil 6. 



In dark- 

 ness. 

 Soil 2. 



1— 



mm. 

 5 

 8 

 7 



4.5 

 4 

 4 



3.5 

 4.5 

 3 



2.5 

 2.5 

 3 

 2 



1.5 

 1.5 



0.5 

 0.5 

 0.5 

 0.5 

 0.5 



mm. 



8 

 14 

 17 

 20 

 16 

 13 

 12 



9 



mm. 

 3 

 10 

 10 

 12 

 10 

 9 

 7 



A 



mm. 



7 

 14 

 16 



8 



3 



0.5 



0.6 



mm. 



3.5 



5.5 

 10 

 10 

 11 

 12 



12.5 

 10 

 10.5 

 10 

 10 



8 



8 



7 



6 



4.5 



4.5 



4 



3 



3 



2 



1.5 



0.5 



mm. 



5 



7 



9 

 16 

 19 

 17 

 10 



9 



8 



5 



3.6 



1.5 



1.5 



1 



mm. 



} '\ 



2 

 2 



2 



2 



2 



2 



1.5 



1.5 



1 



1 



1 



0.5 



0.5 



mm. 



2 



3 

 13 

 3.5 

 2 

 0.5 



3— .. 



4 



5_ 



6 _ 



7 



8 





9- - 



8 * 







10 



7 



4.5 



3 



2 



2 



1 



0.5 



3 



4 



3.5 



3 



2.5 



3 



8 



3 



2.5 



3 



2.5 



3 



2 



2 



2 



2 



1 



1 







11 







12..., 







13 







14 







15 







ML... _. 









17 











18... 













19 













20. 











21 













22 _. . 













23 













24 













25- 















26. 















27 

















28 



























