4 8 



Richard H. Boerker 



Classification of Species Based upon the Effect of Soil Moisture upon 



Germination 



Xerophilous Species 



Robinia pseudacacia 

 Acer rubrum 



Pinus divaricata 

 Pinus divaricata 



(F. S.). 

 Pinus resinosa 



Pinus ponderosa (S. 



D.) 

 Pinus ponderosa (N. 



M.) 

 Pinus ponderosaCH..) 

 Pinus ponderosa 



(Id.) 

 Pseudotsuga taxifolia 



(N. M.) 

 Pseudotsuga taxifolia 



(Id.) 

 Pseudotsuga taxifolia 



(Colo.) 

 Pinus monticola 



Libocedrus decurrens 



Eastern Hardwoods 



Xero-mesophilous Species 



Catalpa speciosa 

 (Neb.) 



Eastern Conifers 



Pinus palustris 

 Abies balsamea 

 Pinus strobus 



Rocky Mountain Species 

 Abies concolor 



Abies grandis 



Abies lasiocarpa 

 Pinus contorta 



Pseudotsuga taxifolia 



(Mon.) 

 Pinus ponderosa 



(Mon.) 



Pacific Coast Species 



Pinus ponderosa 



(Calif.) 

 Pinus jeffreyi 

 Pinus coulteri 



Mesophi'ous Species 



Catalpa speciosa 



(Ind.) 

 Qucrcus rubra 

 Be tula papyrifera 



Pinus tacda 



Tsuga heterophylla 



Picea sitkensis 

 Pseudotsuga taxifolia 



(Wash.) 

 Pinus lambertiana 

 Abies magnifica 

 Sequoia washington- 



iana 



In Table VI in every case where conclusions were possible it 

 was noted that the beginning of germination was delayed and the 

 germination period was shortened with the decrease of soil mois- 

 ture. In every case the germination per cent, was highest in the 

 wet soil culture. 



For some unaccountable reason Libocedrus decurrens ger- 

 minated in the very dry and wet cultures but not in the medium 

 wet one. However, the four drought resistant species stand out 



