LIST OF ILLUSTRATIONS. 



PLATES. 



Plate A. 



Quadrat-bisect showing root, distribution 

 of certain dominant and subdominant 

 plains species: A, Aristidu purpurea: 

 B, Bouteloua gracilis; Ar, Artemisia 

 frigida; P, Psoralea tenuiflora; C, 

 Chrysopsis villosa; Y, Yucca glauca. 



Plate B. 



Quadrat-bisect in the half-gravel- slide. The 

 face of the trench was cut along the 

 front of quadrat shown in Plate 25, A: 

 S, Solidago oreophila; A, Allium cer- 

 nwMm/E, Elymus triticoides, fragments 

 of which are shown in blue; C, Cala- 

 magrostis purpurascens; H, Heuchera 

 parvifolia; B, Besseya planiaginca. 



Plate C. " 



Quadrat-bisect showing root systems of 

 shrubs and herbs of the forest floor. 

 This was made along the front edge 

 of the quadrat shown in Plate 27, B: 

 H, Haplopappus parryi; R, Rosaacicu- 

 laris; Pi, Pinu^ flexilis; F, Fragaria 

 virginiana; C, Chamoenerium angus- 

 tifolium; P, Picca engelmanni . 



Plate 1. 



A. One end of a trench used in excavating 



root systems. 



B. Distichlis spicata, showing the long rhi- 



zomes and shallow roots. 



Plate 2. 



A. A prairie of eastern Nebraska in June, 



Erigeron ramosus and Meriolix scr- 

 rulata in the foreground, and bushy 

 Psoralea tenuiflora in background. 



B. An area dominated by Agrostis hiemalis, 



with Allium mutabile, Achillea mille- 

 folinm, and Stipa spartea. 

 Plate 3. 



A. Andropogon furcatus. 



B. Andropogon scoparui^. 



C. Andropogon nutans. 



Plate 4. 



A. Pani'Cum virgatum, showing rhizomes, 



coarse roots, and complete single root. 



B. Stipa spartea. 

 Plate 5. 



A. Kaleria cristata. 



B. Elymvs canadensis. 

 Plate 6. 



A. Sporoholus longifolius. 



B. Bouteloua gracilis, excavated near the 



quadrat shown in text-figure 1. 

 Plate 7. 



A. Silphium lacinialum, roots partially exca- 



vated. 



B. Amorpha canescens, showing the wide 



lateral spread. 

 Plate 8. 



A. Kiiltvia glufinosa, roots partially exc:i- 



Plate 8 — continued. 



B. Glycyrrhiza lepidota; a' is a continua- 

 tion of a. 

 Plate 9. 



A. Astragalus crassicarpus, mature root 



system. 



B. Astragalus crassicarpus, showing root of 



young plant. 



C. Baptisia bracteata. 

 Plate 10. 



A. Psoralea tenuiflora, the tap root decayed. 



B. Psoralea argophylla, showing entire root 



in center. 

 Plate 11. 



A. Brauneria pallida. 



B. Lygodesmia juncea, in two sections. 



C. Lcspedeza capitata. 

 Plate 12. 



A. Ccanolhus ovatus, root of a thirteen-year 



old plant; a' is a continuation of a. 



B. Amorpha canescens; a' is a continuation 



of a. 

 Plate 13. 



A. Symphoricarpos vulgaris, showing fine 



network in surface soil. 



B. Rhizomes and runners of Symphoricarpos 



vulgaris; the horizontal line is the 

 ground line. 

 Plate 14. 



A. Rhus glabra, a portion of the root network 



with ascending rootlet a. 



B. Rhus glabra, with ascending rootlets. 

 Plate 15. 



A. Corylus americana, the roots shown in 



two sections. 



B. Rosa arkansana, the roots shown in two 



sections. 



C. Corylus americana, rhizomes and roots 

 Pl.\te 16. 



A. Rosa arkansana, showing method of 



propagation. 



B. Rhus glabra invading subclimax prairie. 

 Plate 17. 



A. Yucca glauca, showing the multicipital 



stems and rhizome habit. 



B. Prairie of southeastern Washington. 



C. Meter quadrat in the prairie, showing 



Balsamorhiza, Festuca, Lithospermum, 

 and Hieracium. 

 Plate 18. 



A. The plains association near Colorado 



Springs, showing Aristida purpurea 

 bunches in Bouteloua gracilis turf. 



B. Psoralea tenuiflora, in two sections. 



C. Yucca glauca. 

 Plate 19. 



A. Stipa comata. 



B. Petalostemon candidus. 



C. Eriogonum jamesii. 

 Plate 20. 



A. Short-grass plains, showing Bouteloua 



gracilis and Opuntia polyacantha. 



B. General view of the sandhill community. 



V 



