A CLUSTER OF EXTRA FLORAL NECTARIES 



Nectar is ordinarily thought of as a product of flowers, but some plants also excrete it from 

 leaves and stems. I'his photograph of a cherry leaf-stem gives a vivid idea of the pro- 

 fusion with which nectar-glands are sometimes formed outside the flower. Three large 

 extra-floral nectaries can be seen on the stem, while the margin of the leaf bears half a 

 dozen more, most of them not functional. When they are functional they are visited 

 by ants and various other insects, but their presence seems to be of no particular advantage 

 to the tree. Highly magnified. (Fig. 15. j 



