II DEVELOPMENT AND ENVIRONMENT 39 



of the 

 move- 

 far as 



to an 

 ing of 

 which 



expressed doubts as 

 to the importance 

 of the stomata in 

 regulating transpir- 

 ation, but such is 

 certainly their 

 function in the 

 cotton plant. Con- 

 sequently, an ex- 

 amination 

 stomatal 

 ments, so 

 they are at present 

 known, is necessary 

 understand- 

 the way in 

 the stem 

 loses water. 



The stomata of 

 Egyptian cotton 

 plants are found 

 on both surfaces of 

 the cotyledons ; on 

 the hypocotyl and 

 stem, and on both 

 surfaces of the foli- 

 age leaves. 



A full grown 

 stoma is about "04 

 mm. in length, and 

 the mean fre- 

 quency of these 

 organs in each 

 square mi 1 1 i- 

 metre has been 

 found to be as 

 follows. 



I'i 



=01 

 O I 

 O I 



"I- 1 



- 144 cm. 

 below the surface 



\ 



V 



i 



Fig. 38. — Regeneration 



OP THE Root SYSTEM. 



200 cnh below 

 the surface 



Showing crop of new roots developed in six 

 weeks from merely one uninjured lateral (the 

 dotted line). Tracing from a blue-print of 

 the root itself, after floating it upon a sheet 

 of glass. See Fig. 35 and also 30. 



