Germination of Forest Trees 63 



over 21 germinated first in the wet soil. In both the xerophilous 

 and the xero-mesophilous species the tendency is to germinate 

 first in the wet soil. In the experiments on soil texture the 

 tendency is for the xerophilous species to germinate first in the 

 gravel and sand, for the xero-mesophilous to germinate first in 

 the sand, and for the mesophilous species to germinate first in 

 the sand and loam. This is a most interesting result, in view of 

 the moisture and air conditions in these soils. On the whole the 

 tendency is for most of the species to begin germinating in the 

 sand and gravel ; about 25 out of 32 species began germinating in 

 either of these two kinds of soils. In the soil texture data it is 

 interesting to compare the germination of xerophilous and meso- 

 philous species in the gravel. Such a comparison shows 7.50 

 xerophilous species germinated first in the gravel and only 1.50 

 mesophilous species. 



From Table XIV it is apparent that out of 34 species 14.5 

 showed the shortest germination period in open light and that the 

 number of species of this kind decreases as the intensity of the 

 light decreases. In other words shade increases the length of the 

 germination period. In the soil moisture experiments the 

 shortest periods were in 25 species out of 27 found in the dry 

 or the medium wet soil. In the soil texture experiment the 

 species are very evenly distributed. Loam and gravel, the two 

 extreme soils from the standpoint of soil moisture and soil aera- 

 tion, show the greatest number of species and the sand culture 

 shows the least. This fact is in harmony with the idea that 

 favorable conditions, such as we found in the light and the soil 

 moisture experiments, lengthen the period of germination. 



Table XV shows that out of 14 drought-enduring species 12 

 reached their greatest germination per cent, in the shade ; out of 

 13 xero-mesophilous species 10 reached their highest per cent, in 

 the shade; and out of 8 mesophilous species 7 reached their 

 highest per cent, in the shade cultures. Out of a total of 35 

 species, 29 germinated highest in the shade cultures. Out of 27 

 species tried in the soil moisture experiments 23 germinated 

 highest in the wet soil and 4 highest in the medium soil. None 

 reached their highest per cent, in the dry soil cultures. Among 



