NORMAL STOMATAL MOVEMENT. 



105 



3a.m. 



3 p.m. 



PIG. 34. Daily periodicity of stomatal movement in Fouquieria, splendens. Sto- 

 mata, upper surface of primary leaves. (Curve a, fig. 37.) 



3a.m. 6 9 12m. 3p.m. 6 9 



FIG. 35. Stomata, lower surface, secondary leaves of Fouquieria splendent, July 27- 

 28, 1906. Curves of extreme and mean transverse diameter. (Curve b, fig. 37.) 



NORMAL STOMATAL MOVEMENT. 



The amplitude of movement in the stomata of the ocotillo is not as great 

 as in Verbena, a transverse diameter of 12 micra, when fully open, being 

 reached usually only by the stomata found on the primary leaves. The usual 

 maximum pore fully open does not often exceed 10 micra. As in Verbena, 

 the period of minimum starch content is that of maximum opening. Tables 

 51 and 52 and the curves in figs. 33 to 37 will give a fair idea of the usual 



