BOTANY OF THE LIVING PLANT 



„ h .n All tl„ I together in 



: » lI, K the Sl . . _. n :j 



V „ thai the stoma* provide ! ^> ra P ld 



tW een the leaf 1 -n.i the ■t"°£**; 



„f th-.r huge Dumbei . but also for the less 



ob > .n that far mon diffusion ? > *nU wru tokea place through a 



W ch toma, than through a port « dimensions. 



1 hl ' s prim iplr I .1.1 DC illustrated t.v .- fen ■:, I > to I M" Omenta on the diffusion 

 oJ ,, ^ metal discs securely hxed to the tops 



Fie. ft. 

 oa in median section, and also in surface-view. The 

 ■w the position of its nuard cells in the open state ; the dotted 

 iw tbeir position in I 1 state. 



<.f l;I ten- jars containing water. The evaporation through the 



■i be followed by noting the loss in weight of the jars. In 



irticular i ment the evaporation from a jar covered by a disc with 



entimeter in diameter was compared with that from a 



second jar in which the di* bore four smaller holes equal in combined area 



to that of the ringli in the first jar. The evaporation from the second 



rably r than that from the first. Thus subdivision 



of j f&ciency as channels of diffusion. The efficiency 



of mi like those of stomata is therefore very high. 



Th it night, togetlicr with the fact that the 



t of the epidermi rooted-over by the cuticle, through which 



to a limited extent only, results in the avoidance 



