A CLUSTER OF PECAN NUTS 
The pecan is a species of hickory and its nuts, here shown natural size, are enclosed in pods 
or husks. 
It is becoming an important crop in the southern states, due to the isolation 
and propagation of superior varieties instead of dependence on mixed seedlings, as in the 
past. 
ization of species of many genera. Our 
sycamore, Platanus occidentalis, for ex- 
ample, is one of the most rapid growing 
of our hardwood trees. But it is 
afflicted with a fungus disease which 
causes the leaves to fall almost imme- 
diately after they have appeared in the 
spring. The restored foliage does not 
appear to suffer, however, and the tree 
Photograph from the United States Department of Agriculture. 
(Fig. 13.) 
does not appear to be greatly retarded 
in its annual growth, for notwithstand- 
ing this infirmity, the tree holds first 
place in size among North American 
hardwoods. But the tree is being 
replaced by the European sycamore or 
plane (Platanus orientalis) in street and 
landscape plantings, as the exotic species 
appears to be immune to this disease. 
4 Lamb, W. H., in JouRNAL oF HEreEpity, VI, 9, pp. 424-428, September, 1915. 
