22 



Göte Turesson 



of these were almost full-grown at the time of experimenting, which adequately ex- 

 plains the slight deviations in some cases. Three vigorous shoots were capped in 

 the field with black paper capsules and were allowed to remain so for 48 hours; 

 the following five refer to cut twigs placed in water flasks in the dark room for 

 48 hours; the next three (cut twigs) were placed in the laboratory in very diffuse 

 hght, and the last seven twigs were exposed to direct sunlight the intensity of which 

 amounted to 7—8 during 4 hours. The figures indicate the magnitude of the 

 angles formed by the twigs with the perpendicular. 



Table XIII. 







Original 

 position 



Final position 



Deviation 



1 



Field trial 



100 



93 



+ 7 



o 



Ù 



» » 



85 



77 



1 o 



+ 8 



3 





103 



95 



+ 8 



4 



Dark room 



84 



84 



± 0 



5 



> > 



82 



78 



+ 4 



6 



» t 



84 



82 



+ 2 



n 

 t 





Ii 



bb 



I O 



8 



> » 



90 



86 



+ 4 



9 



Diffuse light 



58 



52 



+ 1 



10 



» » 



72 



64 



+ 8 



il 





76 



73 



+ 3 



12 



Direct sunlight 



82 



83 



— 1 



13 



* » 



83 



87 



— 4 



14 



> Ï 



86 



88 



— 2 



15 



T) » 



60 



65 



— 5 



16 



<t » 



57 



59 



2 



17 



» )> 



79 



81 



2 



18 



» » 



74 



75 



~ 1 



Similar experiments with Cotoneaster integerrima are tabulated in table XIV. 

 The first four twigs were measured after 18 hours; the last four were exposed for 

 three hours to direct sunlight, the light intensity being 10 — 12. 



