ni 



ILLUSTRATIONS. 



PAOB. 



Plats 1& 



A. CarMM rtr"*^* abowinc awto of 



cildedflilnr(CoUptebnmi(l) 

 Tueaon. Arisona 00 



B. Datoa pino dying >e a reault of the 



work of kancaroo-rata (Dipodo- 

 mya dewrti), Glamio, California 90 

 Platb 19. 



A. Aapeo indioating an early fire, and 



aagebniah altemea, a recent one, 

 Strawbony Can>-on, Utah 92 



B. Artemiiia frUtida indicating an old 



fallow field. Warbonnet Canyon, 



Pine Ridge. Nebraska 92 



Plat* 20. 



A. Opuntia comanchica indicating over- 



grased pastures, Sonora, Texas. 96 



B. Euphorbia ni.irRinata marking road- 



ways, Walscnburg, Colorado ... 96 

 Plate 21. 



A. Stipa Andropogon association, Lin- 



coln. Nebraska 120 



B. Stipa spartea consociation, Halsey, 



Nebraska 120 



C. Andropogon scoparius consociation. 



Medora, North Dakota 120 



PLATB22. 



A. Koderia cristata and Andropogon 



copaiius association. Agate. Ne- 

 braska 124 



B. Erigeron ramosus society, Lincoln, 



Nebraska 124 



C. Detail of society of Paoralea tenui- 



folia and Erigeron ramosus. Lin- 

 coln. Nebraska 124 



Plat* 23. 



A. Association of Andropogon furcatus. 



nutans, soopariua and Bouteloua 

 racemoea. Peru, Nebraska 132 



B. Society of Silphium laciniatum in 



Andropogon-Agropyrum associa- 

 tion. Salina. Kansas. 132 



Platb 24. 



A. Stipa comata consociation. Pine 



Ridge. South Dakota 136 



B. Agropyrum glaucum consociation, 



Winner. South Dakota 136 



C. Detail of aaaodation of Stipa comata. 



Sporoboluscryptandrusand Bou- 

 teloua gracilis. Colorado Springs. 



Colorado 136 



Platb 25. 



A. Agropynun glaucum and Bouteloua 



gracilis aaaodation, Vermpjo Park, 

 New Mexico 138 



B. Detail of AKropyrum-Bulhilia asso- 



ciation. Winner, South Dakota. . 138 



C. Polygala alba society in Bouteloua 



consociation. Interior. South 



Dakota 138 



Plate 26. 



A. Bouteloua-Bulbilis association, with 



Bubclimax of Andropogon scopa- 

 rius and Bouteloua racemosa on 

 butte, Stratford, Texas 140 



B. Dense sod of BulbilLs and Bouteloua, 



Goodwell, Oklahoma 140 



PAGE. 



Plate 26 Continued. 

 C. Open sod of Bouteloua. Dumas, 



Texas 140 



Plate 27. 

 A. Muhlenbergia gracillima and Boute- 

 loua gracilis. Manitou. Colorado. 142 

 p. Detail of Bouteloua KracilLs, Ver- 



mejo Park, New Mexico 142 



C. Hilaria janiesii on a saline plain. 



Delta, Colorado 142 



Plate 28. 



A. Bouteloua-Hilaria association. Em- 



pire Valley, Arizona 144 



B. Bouteloua rothrockii and Aristida 



divaricata, Santa Rita Reserve, 

 Tucson, Arizona 144 



C. Bouteloua racemosa consociation. 



Oracle, Arizona 144 



Plate 29. 



A. Bouteloua- Aristida association. 



Sweetwater. Texas 146 



B. Bouteloua gracilis, Scleropogon brevi- 



folius and Hilaria mutica (valley). 

 B. eriopoda, gracilis, racemosa 

 (hills). Van Horn. Texas 146 



C. Bouteloua gracilis, hirsuta. eriopoda, 



and Aristida divaricata, Jornada 

 Reserve, Las Crucea, New Mex- 

 ico 146 



Plate 30. 



A. Agropyrum-Festuca association, 



The Dalles, Oregon 150 



B. Agropyrum consociation. MisBoula, 



Montana 150 



C. Agropyrum consociation on "scab" 



land. John Day Valley, Oregon. 150 

 Plate 31. 



A. Stipa setigera consociation in track- 



way, Fresno, California 150 



B. Avena fatua consocies, with relicts of 



Stipa setigera and eminens. Rose 

 Canyon, San Diego, California. . 150 

 Plate 32. 



A. Artemisia tridentata consociation, 



Henefer. Utah 154 



B. Artemisia tridentata consociation, 



Garland, Colorado 154 



C. Artemisia arbuscula consociation, 



Evanston, Wyoming 154 



Plate 33. 



A. Subclimax sagebrush in bad-land val- 



leys. Hat Creek, Nebraska 158 



B. Altemes of Artemisia and Kochia, 



Strevell, Idaho 156 



C. Sarcobatus, Chrysothamnas, Atri- 



plex and Artemisia, Vale, Oregon 156 

 Plate 34. 



A. Atriplex confertifolia consociation. 



Delta, Colorado 158 



B. Atriplex corrugata consociation, 



Thompson, Utah 168 



C. Atriplex lentiformis consociation. 



Salton Sea. California 158 



Plate 35. 



A. Contact of Basin sagebrush with 

 Coastal sagebrush and chaparral, 

 Campo. California 160 



