VICTOR E. SHELFORD. 



of soil water is great. Such plants have xerophytic structures 

 (which tend to check the loss of water] developed far beyond the 

 requirements of the atmospheric conditions surrounding their vegeta- 

 tive parts. It is improbable that the animals inhabiting a bog- 

 vegetation field-stratum would select atmospheric conditions such 

 as produce equally xerophytic structures under favorable soil 

 conditions. We may therefore expect disagreement. The smaller 

 plants such as fungi, algse, etc., are related to the strata of soil and 

 atmosphere exactly as the smaller animals and as much disagree- 

 ment is to be expected between such plants and the rooted 

 vegetation as between the rooted vegetation and animals. It 

 must also be noted that the xerophytic structures of the plants 

 of unfavorable soils may have important influence upon ecto- 

 phytic plants and animals and in part counteract the effect of 

 favorable atmospheric conditions. 



The second type of disagreement is represented by cases in 

 which the vegetation is said to lag behind. We have noted that 

 on the clay bluff, conditions become favorable for inconspicuous 

 plants and forest animals as soon as the growth of the pioneer 

 vegetation gives shade to the soil. In other cases woody vegeta- 

 tion remains in situations where the conditions have become 

 unfavorable for it and the less conspicuous plants and some of 

 the animals have disappeared. We may expect lack of accord 

 within and between plant and animal communities under such 

 conditions. In these cases, however, conditions are only tem- 

 porarily out of adjustment, due to rapid physiographic changes 

 and we note from the data presented that plant and animal 

 communities are usually in agreement. The exceptions are often 

 apparent only and due to the emphasis of species instead of 

 mores and growth form. 



VI. GENERAL DISCUSSION. 



At this point we may note certain aspects of the basis for the 

 organization of ecology into a science. It is possible to char- 

 acterize the communities of the forest in physiological terms 

 though we cannot be as definite as is to be desired, until mores 

 have been studied in detail. Taking the communities one by 

 one and stratum by stratum we may note obvious characters. 



