Germination of Forest Trees We 
terial will produce smaller seeds than in cases where there is a 
great accumulation. It has been repeatedly shown that after a 
seed year the amount of accumulated food in the medullary rays 
and other food accumulation centers is reduced to a minimum. 
The site upon which the tree grew, naturally, is intimately con- 
nected with the amount of food material available for the embryo 
of the seed. For the same reason the climatic variety of the 
tree probably affects the size of the seed. At least, it is common 
knowledge that the California variety of Pius ponderosa has 
seeds which may weigh from three to four times as much as 
those of the South Dakota variety. While most of these points 
remain to be proven experimentally, they have been indicated to 
the writer by various experiences and are put forth as interesting 
hypotheses awaiting experimental proof. Whatever the cause of 
the varying size of seeds is, it is quite evident from the amount 
of literature on the subject that this phenomenon has attracted 
considerable attention in recent years: both in silviculture and 
agriculture. ‘ 
That heavier and larger seeds furnish a better germination per 
‘cent. than light ones has been recognized for a long time by 
European silviculturists. The physiology of germination indi- 
cates that large seeds should succeed better, and repeated ex- 
periments by Buhler, Friedrich, Haack, Eisenmenger, and others 
establish this beyond much doubt. In fact forestry practice 
throughout Europe and especially in Prussia shows that smaller 
seeds produce fewer plants per hectare than larger ones in broad- 
cast sowing. Favorable and unfavorable site and season condi- 
tions produce far less variation in the final results in cases where 
heavy seeds are sowed. ; 
In 1904 Blumer (22) conducted at the seed laboratory of the 
United States Department of Agriculture a series of tests upon 
certain American species of tree seeds. Pinus ponderosa from 
the Rocky Mountains and Pinus divaricata showed the highest 
germination but Pinus ponderosa from Oregon germinated ex- 
ceedingly slowly, a feature which also characterized Pseudotsuga 
taxifolia from the Pacific Coast. He noted great variation in 
the number of seeds per pound for the same species, especially 
