36 Richard H. Boerker 
degree of light, namely, the number of days which elapsed before 
germination began, the number of days in the germination period, 
and lastly the final germination per cent. 
The number of seeds used of each species in each culture made 
was as follows: 100 seeds each of Catalpa speciosa, Acer rubrum, 
Gleditschia triacanthos, Pinus taeda, Pinus ponderosa (Idaho), 
Abies grandis, Abies lasiocarpa, Pinus ponderosa (Mon.), Pinus 
ponderosa (Harney), Pinus ponderosa (Calif.), Pinus jeffreyi, 
Pinus lambertiana, Pinus coulteri, Abies magnifica, and Pseu- 
dotsuga taxifolia (Wash.) ; 25 seeds of Quercus rubra, 400 of 
Betula papyrifera, and 200 seeds of all other species. 
When a number of check cultures were combined as was noted 
previously it became necessary to average the results obtained in 
several cultures under the same set of conditions. Thus the check 
cultures used in each series show the same data in every case. 
Three cultures of each of the following species were averaged 
together: Catalpa speciosa (Ind.), Pinus strobus, Quercus rubra, 
Pinus divaricata, Robinia pseudacacia, Betula papyrifera, Pinus 
ponderosa (S. D.), Pseudotsuga taxifolia (N. M.), Pinus pon- 
derosa (N. M.), and Pinus ponderosa (Calif.). Two cultures of 
each of the following species were averaged together: Pinus 
palustris, Pinus resinosa, Pinus jeffreyi, Pinus lambertiana, and 
Pinus coultert. All other species in the check cultures were 
planted but once. 
In Table I 10 species out of a total of 14 germinated in the 
dense shade before they did in the open light culture. Only 
one species, Pinus palustris, germinated first in the open light, 
one species, Gleditschia triacanthos, did not germinate in the open 
light at all, and two species germinated simultaneously in all three 
cultures. Pinus strobus germinated 8 days earlier in the dense 
shade than in the open light, Pinus divaricata 2 to 4 days, Pinus 
resinosa 10 days, Pinus taeda 2 days, Catalpa speciosa 2 days, 
Quercus rubra 14 days, Robinia pseudacacia 2 days, and Acer 
rubrum 4 days. 
In 9 cases the germination period is longer in the dense shade 
than in the open light and, considering the shade cultures together, 
