315 



Bupatoriinn purpurcuvi iiiaadafuiii Salix spp. 

 Hypericum kalmianmn Scleria trigloincrata 



Juncits balticus littoraUs Solidago graminifolia 



Liatris spicata Spiraea salicifolia 



Invading species, none of which are abundant 



Allium cernuum Rudbeckia snbtoincnfosa 



Amphicarpa monoica Smilax ecirrhata 



Aster macrophyllus Sanicnla manlandica 

 Geraniiifu carolinianum In burns : 



Nepeta cataria Apoeynum androsaeiuifoliitm 



Polygonum persicaria BpUohium angnstifolium 



Prunella vidgaris H clianthns grosseserratus 



Quercns alba (very few) Popuhts deltoides 



Quercus macrocarpa (few) Populns tremnloides 



Species whose occurrence is accidental 

 Apios tuberosa Cyperits rividaris 



Cafalpa speciosa (planted) Krigia amplexicanlis 



Cirsium arvense 



THK BLOWOUT ASSOCIATIONS 



Blowouts are open sandy places evacuated by the wind. They 

 may occur in almost any of the associations that inhabit sandy ground. 

 They are usually started during the winter when the ground is not 

 well protected by vegetation. Once begun, however, any wind with 

 sufficient power to move sand may effect their greater development. 

 As a rule, in this region vegetation is more than able to keep pace 

 w^ith any blowing that may take place, and so there is but little blow- 

 out development during the growing season. Blowouts are especially 

 liable to occur in the sand ridges, no matter whether these are ten- 

 anted by the heath, the Liatris scariosa, or the Quercus vclutma asso- 

 ciation. The blowouts of greatest extent occur in the Quercus velu^ 

 tina association, more especially where trees have been removed. 

 This is because the shade from the oaks has reduced the density of 

 the vegetation underneath them and left more ground exposed to 

 the wind. 



In general, the blowouts are elliptic to oval in shape with their 

 major axis north-northeast or north-northwest. Occasionally a cir- 

 cular blowout may be found and less frequently crescent-shaped ones. 

 Winds from all directions of the compass are responsible for blow- 

 outs of greater or less extent, but the largest ones are formed by 



