210 



In Figure 3 a pair of stomata is shown in which only throe guard cells 

 were formed. In this case the apertures are closed by the movement of 

 the two outer guard cells only. 



These deviations from the general order, position and number of 

 stomata in Trillium iiirulc also obtains, but to a less extent, in other spe- 

 cies of the genus Trillium. It is' also in keeping with other deviations, for 

 which the genus Trillium is noted, such as monstrosities in the leaves 

 themselves and in the parts of the flower. Interesting questions are con- 

 nected with the twin, triple and grouped stomata of Trillium nivalr and 

 other plants as to their complete development, the real causes of their 

 arrangement and their physiological reactions. 



Frc 1. Trillium Nivale. Stomata from outside of sepal showing double and triple 

 groups over one respiratory cavity, x ca. 100. 



