ROOT SYSTEMS OF TRUE-PRAIRIE SPECIES. 



39 



by a few less xerophytic species; many of the species of the high 

 prairie are absent, but are replaced in part by others of a more meso- 

 phytic kind. The dominant grasses, each often covering small areas 

 with a pure or nearly pure growth, are Andropogon furcatus, which 

 sometimes reaches a height of over 6 feet, Panicum virgatum, and Poa 

 pratensis (plate 6). Species of considerable importance are Sparlina 

 cynosuroides, Bouteloua gracilis (especially where the soil is lighter in 

 composition), Solidago canadensis, Glycyrrhiza lepidota, Aster multi- 

 florus, Poa compressa, and Solidago missouriensis. Other common 

 species are Agropyrum glaucum, Physalis heterophylla, Polygonum 

 muhlenbergii, Artemisia gnaphalodes, Zizia cordata, Callirhoe alcozoides, 

 Eragrostis pectinacea, Achillea millefolium, and Veronica serpyllifolia. 



Fig. 13. 

 A meter quadrat in the true- 

 prairie community at the 

 lowland station at Lincoln, 

 Nebraska. Af or //// , An- 

 dropogon furcatus; C, Chce- 

 tochloa viridis; Ca, Carex sp ; 

 E, Euphorbia maculata; G, 

 Glycyrrhiza lepidota; O, Ox- 

 alis stricta; P or^^s, Poa 

 pratensis; Pa, Panicum vir- 

 gatum; Ph, Physalis heter- 

 ophylla; Po, Polygonum 

 muhlenbergii; S, Spartina 

 cynosuroides; So, Solidago 

 altissima; T, Tri folium 

 pratense. 



A carefully selected quadrat, typical of this low-prairie area, is shown 

 in figure 13. The control of the three dominants mentioned above 

 may be seen at a glance. This contrasts rather strikingly with the 

 vegetation shown in figure 11 (cf. also plates 4, b, and 6, a). 



Bisects along the sides of these two quadrats reveal some interesting 

 root relations. In plate A, a bisect along the lower portion of the 

 quadrat (fig. 11) on the high prairie may be seen. The above-ground 

 parts in this quadrat are shown in plate 5, a. These bisects are made 

 in the following manner: After charting and photographing the vege- 

 tation, a trench is dug at the side of the quadrat, care being taken to 

 have the wall corresponding with the side of the quadrat cut smooth 

 and perpendicular. Then, by the use of a hand-pick, the soil is care- 



