126 



One of the most noteworthy plants is a species of Geaster, which 

 is abundant in each of the five areas, especially in open woods or 

 near the edge of the forest. 



Although the total number of species in the association is large, 

 the number per unit of area is scarcely greater than in the prairie. 

 Counts of a series of Cjuadrats each two meters square, in the Win- 

 nebago area, showed an average of 6.5 species per cpiadrat. The 

 forest there was rather open, with a thin deposit of mold, and the 

 conditions for plant life near the optimum. In the whole field of 

 about twenty acres (8 hectares) 32 species occurred. The number 

 of species in the whole association is large, as might be expected in 

 a type of such wide distribution and extent, but less than half of the 

 total live in any one of the five areas examined. The small number 

 in any individual station and the large number for each quadrat pro- 

 duce a monotonous unifomiity throughout the association and pre- 

 vent the recognition of definite consocies. 



The following list gives the ecological grouping- of the component 

 species. 



A. Species typical of the black oak association 



1. Trees: 



Qucrcus velutina Gary a cordiformis 



Quercus luarilandica 



2. Perennial herbs : 

 Pteris aquilina 

 Smilacina stellata 

 Gomandra ninhcllata 

 Fragaria virginiana, var. 



il lino en sis 

 Potentilla arguta 

 Potentilla canadensis 

 Liipinus perennis 

 Dcsniodiinn illinoense 

 Bnphorbia corollata 

 Gallirhoe triaugulata 

 Lechea sp. 



Hcliantheninm ma jus 

 Zizia aiirea 

 Asclepias tuberosa 

 Asclepias amplexicaidis 

 Asclepias verticiUata 



Physostegia denticidata 

 Scrophidaria leporella 

 Pentstemon grandiflorus 

 Synthyris Bui Hi 

 Gcrardia grandiflora 

 Pedicularis canadensis 

 Galium pilosum 

 Liatris scariosa 

 Solidago speciosa, var. 



angusfata 

 Solidago nemoralis 

 Aster azureus 

 Rudbeckia hirta 

 Hclianthns occidcntalis 

 Helianthus strumosns 

 Artemisia caudata 

 Gacalia at riplici folia 



