177 . 



Corylus americana Rhododendron nudifloriim 



Gaylussacia baccata Vaccinium pennsylvanicum 



Kalmia latifolia Vaccinium vacillans 



Viburnum acerifolium 



Prominent among the herbaceous plants of this stage are : 



Aspidium marginale Lysimachia guadrifolia 



Aster divaricatus Maianthemum canadense 



Car ex virescens Melampyrum linear e 



Chimaphila umbellata Mitchella repens 



Cypripedium acaule Panicum dichotomum 



Desmodiuni sp. Pedicularis canadensis 



Epigaea repens Polystichum acrostichoides 



GauUheria procumbens Pteris aquilina 



Geranium macidatum Pyrola americana 



Gerardia flava Pyrola elliptica 



Hepatica triloba Smilacina racemosa 



Hieracium venosum Solidago bicolor 

 Solidago caesia 



Oak-hickory forests like the one here depicted constitute the 

 most familiar type of woodland encountered along the trap ridges 

 near New Haven, and in many sites they may represent the 

 ultimate formation. But, under favorable conditions, such a 

 forest is destined to give way to a still more mesophytic type. 

 And here again the light requirement of the various trees involved 

 seems to be an important factor in determining their behavior 

 and in conditioning their presence or absence in the ultimate 

 forest. For it is self evident that trees like the chestnut oak 

 and pignut, whose seedlings are unable to develop in any but the 

 lightest shade will tend to become less and less abundant as the 

 forest floor becomes more deeply shaded by the ever denser 

 foliage overhead. Conversely, it is those trees whose seedlings 

 are best able to develop under these circumstances that will 

 ultimately survive. Thus it comes about that the climax forest 

 of any region is composed very largely of those native trees which 

 are most tolerant of shade. Of course the proximate composition 

 of the forest in any given locality is necessarily influenced by the 



