ECOLOGICAL CROSS SECTION OF THE MISSISSIPPI. 



185 



lopsis, C. slans, Vitis cinerea, V. cordifolia, V. palmata and 

 V. riparia, together with Tecoma radicans, find their way. 

 At times the wild grapes entirely cover their support. Echino- 

 cysiis lobata, Convolvulus Septum and Polygonum dume- 

 iorum scandens, twine among the bushes (plate 14, 2). Myo- 

 surus minimus, Ranunculus ahortivus, R. septentrionalis, 

 R. repens, Capsella Bursa-pastoris, Nasturtium dbtusum, 



Cerastium nutans, Stellaria longijolia, Hyp 



mutilum, 



Oenothera 



Volerianella 



Senedo aureus, S. aureus Balsamitae, 



Taraxacum officinale, Brunella vulgaris, Euphorbia humis- 

 irata and Allium cernuum form a mat, together with the sedges 

 and grasses, mainly Car ex conjuncta, C. granularis, C. monile, 

 Scirpus atrovirens, Alopecurus geniculatus, Elymus virginicus, 

 Eragrostis reptans, Leersia virginica, Panicum Crus-galli, 

 and Spartium cynosuroides , covering the intervening ground 

 with verdure. Here and there single plants of Hibiscus 



prommc 



similar 



species of Polygonum, among which P. H arlwrightii 

 is the most striking (plate 17) take possession of large 

 tracts, especially where the ground is somewhat higher. 

 Other species prominent during the summer and autumn arc 

 Baptisia leucantha, Lespedeza capitata, Bidens cernua, Core- 

 opsis aristosa, C. aristosa mutica, Eupatorium purpureum 



E. serotinum, Helenium nudifi 



Iva ciliata, Silphium 



perfoliatum, Vernonia fasdculata and V. 



'eboracensis 

 nevetoides 



Chenopodium ambrosioides and C. ambrosioides anthelmin- 

 ticum, different species of Rumex and Saururus cernuus. In 

 fall the Compositae, especially Aster diffusus and A. salici- 

 folius, are most prominent. Among the plants whose pres- 

 ence is not so readily recognized must be mentioned numer- 

 ous species of Cuscuta. 



There exists a marked difference between the Missouri 

 bottoms of the Mississippi and the bottoms of the River dcs 

 Peres, near the spot where it enters the larger river. The 

 bottoms of the River des Peres at this point show several ter- 

 races, the lower one of which is illustrated (plates 18, 19). 



