STONE: CONTACT STIMULATION 461 
TABLE 2 
Showing Growth of Sunflowers (Helianthus annuus L.) in Contact with Wire Netting. 
Average of One Experiment with Twelve Plants* 
Percentage Gain 
Average Height in Height by 
(Centimeters) Contact 
INormal tes is.5.0 85 ke oe ee 131.9 
Gontact wites..7. 2) s. oe 173.0 31% 
TABLE 3 
Showing Growth of Sunflower (Helianthus annuus L.) in Rows between Wire Netting. 
Average of Two Experiments with 54 Plants® 
Average Dimension and Weight in Centimeters and Grams 
; | Internodes | , | Percentage Gain in 
| Height Length | Weight | Height by Contact 
a EA ee A | | eee (ne A, 
| 
ENO a letter reeves 5. oiovee cus | 114.1 6.9 307.9 
Contact wire 4522s o eee. | 151.2 8.9 302.9 31% 
TABLE 4 
Showing Growth of Castor Bean (Ricinus communis L.) in Contact with Wire Netting! 
Average Dimension and Weight in Centimeters and Grams 
cod Diameter Entecodes) | Weight Percent Gain in 
Stem Nantes | Length | Height by Contact 
SS SS ee ee 
INormalignvent-- 73 1.8 9.2 | 7.8 | 457 
Contact wire...| 99 1.5 Solel t= wee 3 lee oA 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 
2 Normal plants separated from one another. 
3 Normal plants separated from one another. 
4 12 single plants used, 6 in contact and 6 not in contact. 
31 
