FOUQUIERIA SPLENDENS. 9 



guard-cell is turgescent, provides for such movement as obtains in the old 

 condition. 



The dimensions of the stoma of average maturity, in the open and closed 

 positions, are shown in table i . 



Table i . — Ocotillo measurements of two stomata open and closed. 



In point of size the stoma is smaller than such monocotyledonous types as 

 Zebrina and compares, mechanically considered, with the more usual dicoty- 

 ledonous types. 



Fig. 2.— Form of stomatal pore of Fouquieria splendens at various degrees of opening. X 2450. 



The distribution of stomata, together with that of a few other plants, 

 is given for comparison in table 2. 



Table 2. — Distribution of stomata 0} Fouquieria splendens and certain other plants. 



Plant. 



Ocotillo 



Verbena ciliata. 



Celery 



Fuchsia 



Parsley 



Oak 



Number of stomata per sq. mm. in 



Lower 

 epidermis. 



Upper 

 epidermis. 



160 (lOO) 



100 to 175 



175 



100 to 125 



I50 



346 



160 



100 to 175 



Total per 

 sq. mm. leaf. 



320 

 200 to 350 



175 

 100 to 125 



150 



346 



The change of form taken by the stomatal pore during opening may be 

 seen in fig. 2, which was made by carefully drawing the pores of different 



