Camptosorus rhizophyllus Link., walking fern. 

 ^Panicum dichotomum L., prairie-grass. 



Cenchrus tribuloides L., sand-bur. 



Poa compressa L., wire-grass, 

 i Festuca octo flora Walt., fescue-grass. 

 ^-Hordeum jubatum L., squirrel- tail grass. 



Carex Muhlenhergii Schkuhr. 



Cerastium nutans Raf., chickweed. 



Talinum teretifolium Pursh, flame flower. 



Heuchera hispida Pursh, alum-root. 



Ranunculus fascicularis Muhl., early fascicled buttercup. 



Aquilegia canadensis L., columbine. 



Draba caroliniana Walt., spring draba. 



Vicia caroliniana Walt., pale vetch. 

 " americana Muhl., American vetch. 



Amorpha canescens Pursh, lead-plant. 



Oxalis stricta L., yellow wood sorrel. 

 " violacea L., violet wood sorrel. 



Poly gala Senega L., Seneca snakeroot. 



Taenidia integerrima Drude, yellow pimpernel. 



Dodecatheon Meadia L., shooting star. 



Asclepias verticillata L., verticillate milkweed. 



Verbena angustifolia Michx., narrow-leaved vervain. 

 " stricta Vent., hoary vervain. 



Scutellaria parvula Michx., small skullcap. 



Linaria canadensis (L.) Dumont., toadflax. 



Pentstemon hirsutus Willd., hairy beard- tongue. 



Orobanche uniflora L., cancer root. \ 



Houstonia caerulea L., bluets. 



Myosotis virginica (L.) BSP., white forget-me-not. 



Specularia perfoliata (L.) A. DC, Venus' looking-glass. 



Campanula rotundifolia L., harebell. 



Solidago nemoralis Ait., goldenrod. 



Aster ptarmicoides T. & G., upland white aster. 



Antennaria plantaginifolia (L.) Richards, everlasting. 



Brauneria angustifolia Heller, purple coneflower. 



Achillea Millefolium L., yarrow. 



VII. THE FLOOD-PLAIN ASSOCIATIONS 



From the nature of their physiography there are many species com- 

 mon to the climax mesophytic forest {q.v.) and the fairly mature flood 

 plain. The earlier stages of the latter are characterized by a number of 

 rapidly growing trees and a herbaceous undergrowth of great luxuriance, 

 in which the broad "shade leaf" is seen at its highest development. 

 Nowhere is the development of chmbing and twining plants so abundant. 

 The different stages in the development of the flood-plain vegetation 

 are not distinguished in the following list of species. In the list are 



23 



