SYNTHETIC CHARACTERS OF THE COMMUNITY 



67 



P. uniflora, Listera cordaia, Linnaea borealis, and other species prac- 

 tically always appear only in the older (50- to 100-year) timber stands. 

 The first two show marked preference for the Pinus silvestris forest; 

 the others, for the spruce woods. Similar examples could be multiphed. 

 On the other hand, if a timber type is found outside its natural 

 range, its group of characteristic species will not appear, even after 

 hundreds of years of undisturbed growth. The presence or absence of 



Succession 



FiQ. 39. — Development of the characteristic species in three genetically related asso- 

 ciations of the Flemish littoral. {After Hocquette.) 



the group may serve, therefore, as in the alpine foothills, to distinguish 

 natural from planted spruce woods. 



Distribution of Communities and of Characteristic Species. — 

 Ponderous manuals and masses of plant lists tell us with increasing 

 exactness about the occurrence and distribution of the species of our 

 flora. These sources can also be made useful synchorologically by 

 means of the fidelity of species. 



Oftentimes an obscure floristic paper may enable us to predict the 

 presence of a certain association. If several characteristic species 

 occur together in one locality, the presence of the association in ques- 



