THE SCOPE AND IMPOHT OF GENECOLOGY 175 



problems of the origin, variation and grouping in nature of plants are 

 being attacked. 



The importance of genecology for other branches of natural science 

 is especially seen in its relation to plant-geography, both as to questions 

 of species and in regard to plant communities. Tlie signilicance of gen- 

 ecology for the species phase of plant-geography is sufficiently clear 

 and need not be enlarged upon; its importance for the communities may 

 be touched upon here. The far-reaching analysis of plant communities 

 during the last few years, more particularly in our own country, has 

 disclosed the fact that the associations are made up of groups of plants 

 of different »associative value». Some of these species are constantly 

 found, wherever the i)articular association occurs: these are the so- 

 called constants. The rest of the plants belonging to the association 

 vary as to species with the different localities; these are the so-called 

 accessories of the association. On account of the fact that the species 

 belonging to the former group accompany the association over a wide 

 geographical range (in some cases occurring through most of the Scan- 

 dinavian peninsula) the conclusion is drawn that these species do not 

 respond to ecological factors prevailing in the different regional points 

 but remain constant, forming the fixed framework of the association 

 (Du RiETZ, Fries, OsvALD andTENGWALL, 1920). From a genecological 

 point of view this conclusion is not warranted. A genecological study 

 of the constants of the particular association from different geographi- 

 cal points of its distribution area is needed before such a statement can 

 be made. The behaviour of the species found as constants, some of 

 which (as Scotch pine, birch, Vaccinium niyrtiUiis. V. vitis idaea, Ra- 

 nunculus acer) are known to be notoriously variable, points rather to 

 the fact that it is just the ability of these species to respond genotypically 

 to a wide range of different ecological factors that enables them to 

 establish associations in regions climatically dissimilar. The sig- 

 nificance for synecology of an intensive study of this and related ques- 

 tions is evident. 



In summing up the object and contents of this paper it should once 

 more be stated that the study of the species and its hereditary habitat 

 types from an ecological point of view, in other words genecology, in- 

 volves a necessary extension of the field of ecology hitherto pursued, viz. 

 the fields covered by autecology (here meant to imply the ecology of 

 the individual organism) and synecology. When viewed from the 

 standpoint of biology at large the study of the species along this and 

 related lines implies the foundation of an independent speciology along- 



