1O Richard H. Boerker 
of tap root in plants that had been grown in no shade and the 
greatest length of lateral roots and total root system in the no- 
shade plants. This bears out Nikolsky’s experiments along the 
same line. An interesting conclusion reached by Burns is that 
shade reduces the temperature of the soil and delays the time of 
germination. 
The work of Atterberg (9) which is quoted by Burns is given 
here for completeness. Atterberg studied the relation of light 
and temperature to the germination of pine seedlings. He found 
that at a constant temperature of 23° C. 80 per cent. of the seed 
germinated in the absence of light and 87 per cent. in the presence 
of light during practically identical germination periods. Burns 
concludes from this: “ Apparently a high and changing tempera- 
ture, light, and a moist seedbed are essential to satisfactory 
germination.” 
The investigations of Haak (5) and Pittauer (6) have very 
little bearing upon the problem at hand. The former at the 
mycological laboratory at Eberswalde studied the influence of 
season, moisture, temperature, light days and dull, artificial and 
natural light, color of light, intensity and duration of light, and 
the influence of chemicals upon the germination of Scotch pine 
seeds. He found that in lower temperatures germination begins 
considerably later and proceeds much more slowly that in higher 
temperatures, but that the final germination per cents. are about 
the same in either case. He found that certain rays of light were 
beneficial and certain harmful to germination. Pittauer studied 
the effect of different degrees of light and extreme temperatures 
upon the germination of tree seeds of certain European species, 
viz.: beech, black locust, and various conifers. He found that 
germination proceeds more rapidly in light than in shade and is 
most satisfactorily accelerated in diffused light. 
Undoubtedly considerable work has been done in the United 
States by the various forest experiment stations of the Forest 
Service but these results have not been, as far as my knowledge 
goes, published. In a very recent article in Science, Graves (7) 
speaks of such work being carried on at the Wind River Forest 
Experiment Station in Oregon. A recent discovery at this sta- 
