58 UNIVERSITY OF MISSOURI STUDIES [20O 



oblusa, Aspleniuni platyneuron, and Polystichum achrosti- 

 choides are abundant also. Arabis laevigata, A. dentata, and A. 

 Canadensis are common, as is also Erigeron Philadelphicus. 

 These furnish good examples of rosettes. 



c. Fontinales senecionoides. The groundsel associa- 

 tion occupies the upper portion of the fontinal subzone, or often 

 the whole sides of low moist cliffs. Such plants as Senecio 

 aureus, Eupatorium ageratoides, Campanula Americana and As- 

 prella Hystrix are typical. A brief list of plants follow : 

 Woodsia obtusa E. Canadensis 



Cystopteris fragilis E. glaucifolius 



Melica mutica Asprella Hystrix 



Festuca nutans Senecio tomentosus 



Bromus purgans S. aureus 



Elymus striatus S. obovatus 



E. Virginicus 



2. Rupestres clivosae. The clivose vegetation occu- 

 pies those portions of cliffs which are covered with earth. It 

 lies above the fontinal when that subzone is present. It consists 

 of trees, shrubs and a rich variety of herbs. Not only are the 

 characteristic rupestrine plants present, but practically the whole 

 flora of rich deep ravines. The covered cliffs have a mesophytic 

 mixed vegetation, which is hard to separate into definite societies 

 and is best treated as a unit. 



a. Clivosae ostryoides. The ironwood association of 

 clivose trees, shrubs and herbs covers the lower slopes of the 

 cliffs, or in the case of low slanting cliffs, to their summits. 

 Ostrya Virginica, Quercus acuminata, Ulmus fulva, Acer 

 nigrum, Carya amara, and Staphylea trifolia are characteristic 

 trees and shrubs. Th&w^.itv-\t^.ves{Hydrophyllum spp.) and 

 bedstraws {Galium spp.) abound, as do also species of Trade- 



