366 MINNESOTA BOTANICAL STUDIES 



Secondary species : The following species of herbs are char- 

 acteristic : 



Alsiiie longifulia Lycopiis litcidns 



Aster paniculatus Mentha canadensis 



Campanula aparinoidcs Menyanthes trifolia 



Comarinn palustre Naumbergia thyrsi flora 



Dryopteris thelyptcris Scutellaria galericulaia 



Galium trifiduin Siuiu cicutaefolium 



(5) Larix-Picca Associes 



Causes : The appearance of Sphagnum as described on pages 341 

 and 342 may lead up to this associes, following the Chaniacdaphue- 

 Andromeda associes as in the developnient of the climax jiine forest. 

 This has been observed in some places, but in others Larix may ap- 

 pear without being preceded by the Chauiacdaphne-Andromeda as- 

 socies. That this procedure is not to be regarded as normal but 

 rather as a departvu-e from it due to draining, burning, clearing or 

 other disturbance initiating a secondary succession, seems probable. 

 When more evidence becomes available by the study of development 

 in other places in the deciduous forest region, this point will be de- 

 cided. 



Consocies : The associes consists typically of two consocies. 

 Larix laricina and Picca mariana. 



Larix ranges much farther southward than Picea, so that the 

 former is often the only representative of the associes. 



Secondary species : The following shrubs usually occur in this 

 associes : 



Betula puniila Salix cordafa 



Cornus stolonifera Salix discolor 



Salix hebbii Salix petiolaris 

 Salix Candida 



Betula puniila and Salix Candida are often the first to invade the 

 Carex associes and sometimes form a scattering zone between it and 

 the Larix zone. The herbs of this stage are the consocies of the 

 Carex stage with its characteristic secondary species, which usually 

 persist as relicts in the Larix-Picea associes. 



(6) Populus-Bctitla Associes 

 Causes : Further filling in along the edge of swamps by wash- 



