360 MINNESOTA r.OTANJCAL STUDIES 



times it may be acconii)anied by Bcliila papyrifcra or by Querciis 

 coccinca or both. 



Consocies : The usual consocies are Pupiiliis trcmuluidcs, Finns 

 divaricata and Bctnla papyrifcra. To these Oncrcns coccinea may 

 be added for certain areas. Any two or more of these may form 

 a mixture, or in other places the associes may be represented by but 

 one of its consocies. 



In the region of surface rock, near Tower and Ely, Betnla 

 papyrifcra often occurs in socies. The same may be said of P. 

 divaricata in the same area, but more particularly this is true of P. 

 divaricata in areas of out wash sand and gravel above mentioned. 

 In Crow Wing County, Qucrcus coccinea occurs as a consocies. 

 This has not been found to apply elsewhere. In areas of greater 

 water-content in the soil, socies of P. trcmnluidcs may be found. 



Secondary species : Other species of Popnlns, viz. : P. grandi- 

 dcntata and P. balsamifera, usually occur with P. tremnloides, but 

 not in sufficient abundance to rank as consocies. Colonies or socies 

 of P. grandidcntata may occur sometimes. Quercns coccinea is 

 present in many places. 



A number of shrubs are characteristic of this associes in sec- 

 ondary succession : 



Acer spicaliiin Prunns virginiana 



Abuts incana Rihes amcricannm 



Cornns stolonifcra Rosa acicnlaris 



Corylns rostrata Rosa blanda 



Dierz'illo lonicera Rnhus sirigosus 



Loniccro obloiigifolia Vaccijiiiiui canadense 



Prunns pcnnsylvanica Vaccininni pcnnsylvanirmn 



In some areas Alnns crispa may be found with A. incana. Loni- 

 cera hirsnfa, Ribes gracile and Rnbns allcghcniensis occur occasion- 

 ally. 



The herbs of this associes are numerous. The following are usu- 

 ally present : 



Anemone quinqnefolia Cliiuiaphila nmbellata 



Aralia nudicaulis Cornns canadensis . 



Aster cordifoliiis Falcata comosa 



Aster laeris Pragaria virginiana 



Aster macrophyllus Gauliheria procnmbens 



