Senile Changes in Leaves of Certain Plants 299 



TABLE 5 (concluded) 



Number of vine 



Minimum 

 area of islets 



(square 

 millimeters) 



Average area 



(square 

 millimeters) 



Maximum 



area 



(square 



millimeters) 



31 



0.3208 

 0.2819 

 0.1690 

 0.1221 

 0.2698 

 0.3170 

 0.2110 

 0.3500 

 0.2041 

 0.2961 

 0.3000 

 0.3810 

 0.4610 

 0.3097 

 0.2901 

 0.2593 

 0.1376 

 0.1534 

 0.3510 

 0.3489 

 0.3790 

 0.2598 

 0.3098 

 0.2106 

 0.4096 

 0.4597 

 0.3325 

 0.2217 

 0.3017 

 0.4885 

 0.3173 

 0.1337 



0.3337 

 0.2902 

 0.1807 

 0.1375 

 0.3250 

 0.3301 

 0.2291 

 0.4046 

 0.2312 

 0.3045 

 0.3140 

 0.3926 

 0.4743 

 0.3195 

 0.3077 

 0.2823 

 0.1541 

 0.1640 

 0.3946 

 0.3987 

 0.4657 

 0.2965 

 0.3280 

 0.2345 

 0.4845 

 0.5055 

 0.3690 

 0.2503 

 0.3311 

 0.5005 

 3553 

 0.1731 



0.3632 



5 



0.3129 



ft 



0.1910 



7 



0.1634 



g 



0.3644 



9 



0.3453 



10 



. 2623 



32 



0.4400 



33 



0.2909 



34 



0.3178 



35 



0.3313 



36 



0.4061 



37 



0.4881 



38 



0.3309 



39 



0.3205 



40 



0.3001 



41 



0.1654 



11 



0.1751 



12 



0.4363 



13 



0.4511 





0.5018 



14 



0.3321 





. 3507 



18 



0.2511 





0.5085 



19 



0.5410 





0.3889 



20 



0.3053 





0.3818 



23 



0.5171 





0.3807 



30 . 



0.2311 







Average 



0.2961 



0.3229 



3496 







The leaves with the smallest vein islets thus show sizes of islets 8.3 

 per cent below the average for the entire plant, while those with the largest 

 show sizes of islets 8.3 per cent above the average. The degree of variation 

 is distinctly less than that shown by the areas and weights of the leaves 

 themselves, and is not greater than that commonly found in the numerical 

 characters accepted in taxonomic work. This seems to indicate beyond 



