Cyperus filiculmis, Froelichia floridcma, Mollugo verticillata 

 (native?), Corydalis aurea var., Corydalis curvisiliqua, Brdba 

 caroliniana, Cristatella Jamesii, Tephrosia virginiana, both, 

 species of Croton, Bhm canaden^s var., Viola pedata, the Opun- 

 tia, Oenothera rhombipetala, the Androsace, Asclepias amplex- 

 icauliSy Phlox bifida, Ldthospetmum Gmelini, Monarda punctata, 

 and Houstonia minima. 



Quite frequently forest species and introduced weeds find their 

 way to the bars. The former are marked ''f" and tke latter 

 ' V in the list. 



The upland sands are often denuded by winds, less frequently 

 by water. Various species of plants become established upon 

 these fresh surfaces. 



In the dune region of Harrison county, the Leguminosae such, 

 as Cassia, Desmodiiim, Crotalaria, Dalea enneandra, and Stro- 

 phostyles are the first to appear, always with an abundance of 

 root-tubercles containing nitrifying bacteria. 



On the dunes of Muscatine county, the pioneers are Mollugo, 

 the species of Croton and Corydalis, Cyperus Schweinitzii and 

 C. filiculmis, Cristatella Jamesii, Euphorbia polygonifolia, and 

 other prostrate species of Euphorbia, and these are soon followed 

 by other sand and prairie species. 



The Harrison county dunes present a limited number of sand- 

 species not found in the other areas, — in fact but two : Euphor- 

 bia dentata and Lygodesmia rostrata, a rare western species. All 

 other species not especially marked, are of the prairie type. 



The Muscatine dune list of sand-plants is much larger. The 

 following species, not found on the Harrison county dunes, are 

 more or less characteristic of the dune and upland sands of Mus- 

 catine county: 



Commelina virginica Euphorbia polygonifolia 



Polygonum tenue Rhus canadensis var. 



Cycloloma atriplicifolia Opuntia Rafinesquii 

 Froelichia floridana - Oenothera rhombipetala 



Mollugo verticillata Synthyris Bullii 



Draba caroliniana Houstonia minima 



Cristatella Jamesii Aster linariifolius 



Croton capitatus 

 Other sand plants, already mentioned in connection with the 

 other sand-areas, are also found in these dune areas, as may be 



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