210 
In Figure 3 a pair of stomata is shown in which only three 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 Vrillium nivale 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 Vrilliwm 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 nivale 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. 
