LIST OF ILLUSTRATIONS. 



PLATES. 



Plate A. 

 Quadrat-bisect showing root distribution of 

 certain dominant and subdominant 

 species of upland true prairie. Be, 

 Bouteloua curtipendula; C, Carex 

 pennsylvanica; K, Kaleria cristata; 

 Li, Liatris punctata; B, Bouteloua 

 gracilis; Am, Amorpha canescens; A, 

 Andropogon scoparius; At, Aster mul- 

 tiflorus; So, Solidago ?nissouriensis; 

 S, Stipa spartea facing p. 38 



Plate B. 



Quadrat-bisect showing root distribution of 

 certain dominant and subdominant 

 species of lowland true prairie. S, 

 Spartina cynosuroides; P, Poa praten- 

 sis; Af, Andropogon furcatus; G, 

 Glycyrrhiza lepidota; Pa, Panicum 

 virgatum; So, Solidago altissima. 



Plate 1. facin S P- 40 



A. True prairie near Lincoln, Nebraska, 



dominated by tall-grasses and with 

 many herbaceous societies. 



B. Kaeleria cristata in true prairie, eastern 



Nebraska, in June. 



C. Stipa spartea and Solidago rigida, Min- 



neapolis, Minnesota. 

 Plate 2. 



A. Open mats of Bulbilis dactyloides and 



Bouteloua gracilis. Sterling, Colorado. 



B. Closed mat of Bulbilis dactyloides in the 



short-grass-plains association, Bur- 

 lington, Colorado. 

 Plate 3. 



A. Agropyrum glaucum in mixed prairie, 



Ardmore, South Dakota. 



B. Bulbilis dactyloides layer in Agropyrum 



consociation, Ardmore, South Da- 

 kota. 



C. Mixed prairie, Mankato, Kansas. Bul- 



bilis dactyloides and Bouteloua gracilis 

 dominating as a result of overgrazing. 

 Plate 4. 



A. Station in the mixed prairie at Colorado 



Springs, Colorado, in an overgrazed 

 area, photographed shortly after it 

 was enclosed in 1918. 



B. Station in the upland prairie at Lincoln, 



Nebraska. 

 Plate 5. 



A. View along the edge of an upland prairie 



quadrat where the bisect (plate A) 

 was made. 



B. Society of Psoralea tenuiflora floribunda 



in true prairie. 



C. A meter quadrat in the upland prairie 



station at Lincoln. 

 Plate 6. 



A. Prairie near the lowland station at 



Lincoln, Nebraska. 



B. Andropogon furcatus on low prairie. 



C. Panicum virgatum on low prairie. 



Plate 7. 



A. Artemisia filifolia and Stipa comata in 



mixed prairie at Haigler, Nebraska. 



B. Andropogon scoparius in a turf of short- 



grasses near Yuma, Colorado. 

 Plate 8. 



A. Sandhill at Seneca covered with mixed 



prairie. 



B. Typical view of sandhills, Seneca, 



Nebraska. 

 Plate 9. 



A. Bulbilis dactyloides on hard land, Yuma, 



Colorado. 



B. Mixed prairie on sandy loam soil near 



Yuma, Colorado. 



C. Redfieldia flexuosa and Muhlenbergia 



pungens (in foreground). 

 Plate 10. 



A. Overgrazed and wind-eroded sandy area 



near Central City, Nebraska, being 

 reclaimed by cropping with rye. 

 Salsola tragus in foreground. 



B. A sandhill in this area dominated by 



Redfieldia flexuosa, Calamovilfa longi- 

 folia, and Andropogon hallii. 

 Plate 11. 



A. Bouteloua gracilis and Opuntia polya- 



cantha in short-grass plains. 



B. Agropyrum glaucum in competition with 



Bulbilis dactyloides, Limon, Colorado. 

 Plate 12. 



A. Roots of Calamovilfa longifolia in natural 



position at a depth of 3 or 4 feet. 



B. Agropyrum glaucum in mixed prairie, 



Mankato, Kansas. 



C. Root system of Secale cereale excavated 



in sandy soil. 

 Plate 13. 



A. Root system of Cyperus schweinitzii. 



B. Rhizomes and a portion of the root 



system of Bouteloua curtipendula. 



C. Portions of the root systems of alfalfa 



from lowland (left) and upland (right) 

 areas. 

 Plate 14. 



A. Panicum scribnerianum. 



B. Four-months-old Bouteloua curtipendula. 

 Plate 15. 



A. Bisect showing roots of 2-year-old alfalfa. 



B. Root system of Bouteloua hirsuta. 

 Plate 16. 



A. A portion of the extensive root system 



of Stipa viridula. 



B. Root system of 2-year-old alfalfa, in two 



sections. 

 Plate 17. 



A. Root system of Carex pennsylvanica. 



B. Plant of 49-day-old white sweet clover 



grown on lowland (left) and upland 

 (right) plats at Lincoln, Nebraska. 



C. Bisect showing roots and rhizomes of 



Calamovilfa longifolia. 



5 



