VENATION AND SENESCENCE OF POLYEMBRYONIC CITRUS PLANTS 32 1 
Variation in the Size of Vein-islets in Polyembryonic Seedlings 
OF Citrus grandis 
Since some of the more variable factors have been eliminated, the way 
seems clear to take up the principal question: Is there any difference be- 
tween the polyembryonic seedlings as regards the character of venation? 
Only mature leaves were used. The larger plant was labeled A and 
Fig. 4. Photomicrograph showing the venation in a mature leaf of Citrus grandis. X 30. 
the smaller one B, when two were produced from a single seed. When the 
plants were equally large and vigorous, the lettering was purely arbitrary. 
Altogether lOO leaves were examined from each of the A and B series. 
This represents 20 plants and 5 leaves from each plant. 
The only conclusion which these data warrant is that, so far as the 
venation test for senility is concerned, it has failed to reveal any essential 
differences between polyembronic seedlings of Citrus grandis. While there 
is no way of knowing positively the number of polyembryonic plant pairs 
used in this study composed of individuals having apogamous and gametic 
origin respectively, yet there can be little doubt but that the leaves from 
such pairs were encountered and studied in one phase or another of the 
work. Since no marked differences in vein-islet area were discovered, the 
following possible explanations are offered: (i) Since the age of the parent 
