ECOLOGICAL CROSS SECTION OF THE MISSISSIPPI. 



171 



hillsTdc^U- makes its appearance borde 



• the creeks. 



striJ 



Sanicula 



landica and >S'. ma^^ ^j^ndica canadensis. Not infrequent, 



but never abundr 

 pubescens. The s? i^ 

 A. triphyllum, / ' 

 anum. The lat' 



are orchids, especially Cypriped 



Dracontmm 



ebeneum 



there 



are 



large fissures in the limestone rocks partly filled with colluvial 

 soil This plant, — and the same is true for Ophioglossum 



Engelmannij — delights in constant moisture, and the lime- 



overed 



moisture 



How 



ever, since in the immediate vicinity of the Mississippi river 



but 



numei 



tory 



east side of the Meramcc river, where the influence of the 

 Ozark uplift is more pronounced, the dip allows the existence of 

 numerous pockets adapted to the needs of both Botnjchium 

 mrginianum and Ophioglossum Engelmanni. Mosses are 

 abundant, covering the ground and running over stones. 

 Most frequent are Amhlystegium serpens and A. varium, 



and Mnium cuspidatum 



With the advent of sumn 

 vernal-flowering disappea 



Such are Sanguinaria cana- 

 densis and Claytonia virginica. On the other hand, many 

 which during the spring were present as rosettes only now 



begin to bloom, among them the latei 

 Ranunculus, such as R. repens. Hyd 



pearance 



eria max^rophylla make 

 e presence of Passiflorc 



canadensCy 

 their ap- 



of Blephilia hirsuta which takes the place of B. dliata oc- 



dry 



Similarly Cassia nictitans 



replaces C. marilandica. During the summer several addi- 

 tional mosses become evident, principally Cylindrothecium 

 Macounii and Ditrichum pallidum. Cladonia pyxidata is 

 the only lichen occurring with frequency. At the mouth 

 of springs Marchantia polymorpha is regularly met with. 

 In the fall the herbaceous plants are represented largely 



