STONE: CONTACT STIMULATION 



461 



Table 2 



Showing Growth of Sunflowers (Helianthus annuus L.) in Contact with Wire Netting. 

 A verage of One Experiment with Twelve Plants- 



Average Height 

 (Centimeters) 



Normal 131. 9 



Contact wire i73-0 



Table 3 



Percentage Gain 



in Height by 



Contact 



31% 



Showing Groiuth of Sunflower {Helianthus annuus L.) in Rows between Wire Netting. 

 Average of Two Experiments with 54 Plants^ 



Table 4 

 Showing Growth of Castor Bean {Ricinus communis L.) in Contact with Wire Netting 



Average Dimension and Weight in Centimeters and Grams 



Height 



Diameter 

 Stem 



Internodes 



Number 



Length 



Weight 



Percent Gain in 

 Height by Contact 



Normal 



Contact wire. 



73 

 99 



1-5 



9.2 

 8.1 



7.8 

 12.3 



457 

 284 



35% 



were grown between parallel rows of wire netting, the netting being of 

 sufficient distance apart to come in contact with the leaves of the 

 plant. Neither the normal plants nor those in contact with the wire 

 touched each other. The experiments with the castor beans shown 

 in Table 4 were identical with those given in Table 2. This showed a 

 gain of 35 percent in the contact plants over the normal. The re- 

 maining 5 tables (5-9) show the effects of surrounding plants with 

 wire netting, dowels and twine, and fish netting. Since in this series, 

 from 2-6 plants are grown close together, they also show to a certain 

 extent the effects of contact with one another. Both the normal and 

 contact plants were in pairs in Tables 5, 6 and 8a while 7 and 8b were 

 arranged in threes and those in Table 9 contained 6 plants. In 

 Table 7a, a wire netting was suspended overhead by twine and did 

 not come in contact with the soil. From the data given in these 

 tables it is hardly possible to draw exact deductions as to the relative 



■ ^ Normal plants separated from one another. 

 ' Normal plants separated from one another. 

 ^ 12 single plants used, 6 in contact and 6 not in contact. 

 31 



