171] FLORA OF COLUMBIA AND VICINITV 29 



Leersia oryzoides Apios tuberosus 



Polygonum emersum Galium tinctorium 



P. sagittatum 



The northern portion has a more varied flora, the substra- 

 tum of which consists often of Onoclea sensibilis. Certain plants, 

 such as Agrimonia parviflora, grow in dense patches, others 

 are distributed pretty evenly throughout, still others stand 

 in little clumps, or are solitary. As a whole only one as- 

 sociation is discernible, the swamp coneflower association, 

 Paludosae rudbeckioides. There is a carpet of rushes, 

 sedges, and coarse grasses, through which the tall herbs 

 make their way, and form a complete superstratum in late 

 summer and autumn. These are characteristic plants: 

 Onoclea sensibilis Lythrum alatum 



Leersia Virginica Epilobium adenocaulon 



Glyceria nervata Gentiana Andrewsii (rare) 



Eriophorum lineatum Asclepias incarnata 



Scirpus atrovirens Vernonia Drummondii 



Carex conjuncta Eupatorium purpureum 



C. vulpinoidea E. tnaculatum 



C. Sartwellii E. perfoliatum 



Rumex crispus Silphium perfoliatum 



Penthorum sedoides Rudbeckia subtomentosa 



Agrimonia parviflora Helenium autumnale 



Intermediate between the paludose and the uliginose veg- 

 etations is that of the swales. Often a single species occupies 

 a whole swale, but usually there is a brief series of plants with 

 Typha latifolia in the nucleus, then a few broad-leaved amphib- 

 iae, such as Alisiiia or Sagittaria. A swale near More's lake con- 

 sists quite wholly of Typha and Eqiiisetum pratense, the only 

 station for this northern plant. An interesting swale along the 

 Wabash railroad has Juncus effusus in the nucleus with the fol- 

 lowing associates: 



