VENATION AND SENESCENCE OF POLYEMBRYONIC CITRUS PLANTS 317 
islets of leaves from normal plants is compared with the same character * 
in leaves from the chlorotic ones. 
While the vein-islets in healthy leaves showed an average size slightly 
smaller than the size of those in the chlorotic leaves, the difference is well 
ii 
Fig. I. Photomicrograph showing the venation in a mature chlorotic leaf of Citrus grandis 
measuring 16 mm. in short diameter. X 30. 
within the range of variations noted in individual leaves in each series. 
Hence the conclusion is warranted that vigor and nutrition have no measur- 
able effect upon the size of the vein-islets (figs, i and 2). 
Influence of the Size of Leaves upon the Size of Vein-islets in 
Citrus grandis 
One of the most common variations with which one meets is in the 
size of mature leaves borne by a single plant. The polyembryonic Citrus 
seedlings are no exception. Experiments were accordingly made to ascer- 
tain whether this variation in size of the leaf was in any way correlated with 
the size of the vein-islets. 
Only mature leaves were used, but the size of the leaves varied from 10 
millimeters up to 68 millimeters in width. Only the short diameter of each 
leaf is given, taken at right angles to the midrib at the point of maximum 
