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ECOLOGICAL CROSS SECTION OF THE MISSISSIPPI. 



197 



from 



Missouri side 



THE ILLINOIS PLATEAU. 



The wooded area. 



woods of the Illinois plateau, composed mainly of de 



resemble generally those of 



tcau. 



be 



On the 



seem 



Hepatica acutiloba 



countered near Jefferson Barracks, though plentiful at Mera- 

 mec Highlands, is frequently met with in the IlHnois woods. 



The same is true for Anemone pen 

 known only from the dry bottom 



on the Missouri side. Gen- 

 been found near Jefferson 



Barracks. 



Open hillside 



This supports but Httle shrubbery, which, if occurring at all, 

 is composed mainly of Rhus glabra. Grasses are dominant, 

 Poa pratensis being the principal species. It is accompanied 

 by Agrostis scahra, Andropogon furcatus, A. scoparius, 

 Aristida oligantha, Bromus secalinus, Danilionia spicata, 

 Eatonia ohtusata, Festuca fenella, Muhleribergia sdbolijera, 

 Panicum sanguinale, Phleum pratense, Poa annua, and Vilfa 

 aspera. During the spring a number of low growing plants 

 occur, such as Ranunculus fasdcularis, Capsella Bursa-pas- 

 toris, Lepidium virginicum, Viola Rafinesquii, Malva roiundi- 

 folia, Linum virginianum, Fragaria virginiana, rosettes of 

 Oenothera biennis and of various Compositae, of which, at 

 this time, Achillea Millefolium and Antennaria plantagini- 

 Jolia, are most frequent, and further, Androsace ocddentalis, 

 Verbena angustifolia, V. bracteosa and V. urticaefolia, Coman- 

 dra U7nbellata, Rumex Acetosella and Hypoxis erecta. Later 

 are added Abutilon Avicennae, Linum sulcatum, numerous 

 Leguminosae, Gaura biennis, species of Aster and Solidago, 

 Gerardia tenuifolia, Monarda punctata, Croton capitatus and 



C. monanthogynus. 



Creek banks. 



The greater portion of the Illinois plateau having fceen 

 brought into cultivation, the presence of a small stream is at 





