CONCLUSIONS. 



127 



Verbena and ocotillo prolonged darkness results in the opening and possibly 

 the repeated opening and closing of small amplitude, of stomata (see fig. 40). 

 Further, the accumulation of starch in moribund cells has been observed 

 (Dandeno) in the cells of ripe apples when affected by disease. The same 

 result may frequently be seen in leaves (Verbena) in which, through one cause 

 or another, portions of the chlorenchyma have been damaged and killed. 

 When the epidermis is removed many of the cells of such dead areas are 

 removed and stain black with iodine. It very frequently happens that the 



5.30a.m. 6.30 



7.30 



8.30 



9.30 



10.30 



11.30 



12. 30p.m. 



Fig. 40. — Opening (in the morning) and closing (in the afternoon) of stomata 

 in air devoid of carbon dioxid. Verbena ciliata. 



epidermis over such areas, including the stomata, is quite normal. I have 

 noted in several instances that such stomata may be supplied with starch 

 under conditions, as, e. g., in the absence of carbon dioxid, which preclude 

 the accumulation of starch in the chlorenchyma, and when, also, the stomata 

 above normal chlorenchyma do not contain starch (see plate 8, figs. 1 and 2). 

 The stomata may have taken up materials from the underlying moribund 

 cells. The transfer of starch from one cell to another in injured leaves (Bain, 

 1902) appears to be analogous behavior invoked under special conditions. 



