342 



Hareis M. Benedict 



young and of old vines. A certain number of observations made indicate 

 that there are other structural and cell differences, and, while the evidence 

 is not fully conclusive, it is at least suggestive and tends to further support 

 the idea that senile changes occur in the leaves of Vitis. The observa- 

 tions are herewith recorded. 



COMPARISON OF NUMBERS OF STOMATA IN LEAVES OF YOUNG AND OF OLD 

 VINES OF VITIS VULPINA 



Comparisons of numbers of stomata per square miUi meter were made 

 with leaves borne by cuttings grown in distilled water under identical 

 greenhouse conditions. Thin flakes of epidermis were removed with a 

 very sharp razor from different leaves of different cuttings, were mounted 

 in water, and were measured as to the number of stomata. From each 

 flake a vein islet of rectangular form was selected, its area measured, the 

 number of stomata counted, and the number to the square milluxLeter cal- 

 culated. The results are shown in table 56: 



TABLE 56. 



Comparison of Number 



OF Stomata in Leaves 



OF VlTIS VULPINA 







Number of stomata to 1 square millimeter in 





6 vines with 



4 vines Tvith 



6 \Tnes with 







from 5 to 7 



from 8 to 10 



from 20 to 30 







nngs 



rmgs 



nngs 





82 



105 



247 







100 



128 



314 







133 



138 



288 







115 



112 



266 







115 



125 



266 







112 



120 



246 







165 



150 



266 







96 



125 



292 







119 



155 



300 







107 

 112 

 157 





290 







330 







256 







115 





314 







194 





314 







144 





247 







86 











105 













Average 



117 



129 



282 



It has been shown by Mer (1886), by Dufour (1886), and by Schuster 

 (1908) that the "same species of leaf possesses more stomata to a unit of 



