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STOMATA AND DROUGHT RESISTANCE IN MEALIES. 



Champion White Pearl. Midrib fairly strong; upper sur- 

 face few long white hairs ; under surface glabrous ; edge slightly 

 ciliate. 



Johnson County. Midrib very strong; both surfaces and 

 edge smooth. Cuticle, both surfaces 4 microns. 



Cock's Prolific. Midrib not strong; upper surface sparsely 

 hairy; under surface and edge smooth. 



German Yellow. Midrib fairly strong ; upper surface 

 slightly hairy; under surface and edge smooth. 



The stomata were measured from the end limits of the 

 guard cells. By examining the table it will be seen that the 

 number of stomata in nearly all cases is greater on the under 

 than on the upper side. It is rather surprising to find so many 

 stomata in comparison on the upper side, as the leaves usually 

 are far from being vertically placed. The size of the stomata 

 also appears to be related to the number, the larger stomata being 

 found with the lesser number, that is, on the upper surface. 

 The drought-resisting capacity does not seem to bear any relation 

 to the number of stomata. In fact, no drought-resistant 

 characters appear to be present such as special thickening of 

 cuticle, sinking of stomata, etc. My opinion now is that the 

 capability for drought resistance has to do with the presence of 

 a peculiar structure on the epidermis of the leaves in the form 

 of small special groups of absorbing and storing cells, which T 

 think are found in varying numbers according to the species. 



