70 Richard H. Boerker 
plant has to go deep for its moisture. In the cases of Robinia 
and Quercus the greatest length of laterals and the greatest 
length of the tap root was found in the sand or gravel, again 
bearing out the fact that sands and gravels are poor soils for 
retaining moisture. 
THE RELATION OF SIZE AND WEIGHT OF SEED TO GERMINATION PER 
CENT. AND EARLY DEVELOPMENT 
During the process of counting between 100,000 and 125,000 
seeds of various kinds for these experiments the fact that seeds 
of the same species varied considerably in size came to the 
author’s notice very forcibly. In his experience in the woods as 
well as in seed extracting it was often noted that many factors 
may affect the size of seeds. In general, it may be said that the 
size of the seeds of any one species depends upon one or more of 
the following factors: 
ihe size of the cone: 
The position of the seed in the cone. 
The development of the cone. 
The age of the tree. 
The physiological condition of the tree. 
The site upon which the tree grew. 
The climatic variety of the species. 
ON ae: els 
It is an old experience that large cones produce large seeds 
and small cones small seeds. The seeds at the extreme base and 
the extreme apex of the cone are very often very much smaller 
than in other parts of the cone. External conditions such as 
temperature and moisture, may affect in no small degree the seed 
while it is maturing, thus retarding its morphological develop- 
ment. It has been observed that middle-aged trees produce the 
largest cones and the largest seeds, while very young or very old 
trees usually produce small cones and small seeds. The physio- 
logical condition of the tree may affect the size of the seed. 
Since seed crops are dependent upon the accumulated food in the 
tree, it is reasonable to suppose that a paucity of such food ma- 
