XII 



LIST OF ILLirSTKATIONS. 



FAQB. 



Plate 36. 



A. Yellow pine consociation, Pinetum 



ponderosae, Prospect, Oregon 128 



B. Speargrass consociation, Stipetum spar- 



teae, Halsey, Nebraska 128 



Plate 37. 



A. Strawberry society, Fragarile, Pseudo- 



tsu^a forest, Minnehaha, Colorado . . 130 



B. Lupine society, LupinUe plattensis, in 



plains grassland. Hat Creek Basin, 



Nebraska 130 



Plate 38. 



A. Clan of Pirdla elliptica in forest. Lake 



Calhoun, Minnesota 134 



B. Clan of Allium mutabUe in prairie, Lin- 



coln, Nebraska 134 



Plate 39. 



A. Grass associes, Andropogon-Calamovilfa- 



poia (A. scoparius, C. longifolia) , 

 Crawford, Nebraska 136 



B. Ruderal associes, Cleome-Senecio-chledia 



(C. serrulata, Senedo douglasii), 



Sidney, Nebraska 136 



Plate 40. 



A. Aspen consocies, Populies, Estes Park, 



Colorado 136 



B. Sand-reed consocies, Calamovilfies, Craw- 



ford, Nebraska 136 



Plate 41. 



A. Pentstemon socles (P. secundiflorus). 



Crystal Park, Manitou 138 



B. Pulsatilla-Polygonum socles (P. ocdden- 



talis, P. bistorta). Mount Rainier, 



Washington 138 



Plate 42. 



A. Colonies of Eriogonum, Gutierrezia, and 



Chrysothamnus in bad land valleys, 

 Crawford, Nebraska 140 



B. Saxifraga family in alpine gravel (S. 



tolmiei) , Mount Rainier, Washington. 140 

 Plate 43. 



A. Artemisia^Popuhis-ecotone, Fallon, Ne- 



vada 142 



B. Piceor-PopuhiS-mictum, Minnehaha, 



Colorado 142 



Plate 44. 



A. Apparent retrogression of Pinus edulis 



woodland due to local disturbance. 

 Bluff, Utah 146 



B. Apparent retrogression of Pinus ponde- 



rosa due to the successful competition 

 of the grasses with the pine seedlings, 



Missoula, Montana 146 



Plate 45. 



A. Denudation in moorland, the peat-hags 



capped here and there with bilberry 

 (yacdnium myrtiUus); "retrogres- 

 sion" of the cotton-grass moor 

 (Eriophoretum) 150 



B. Degeneration of beechwood due to 



rabbits. Holt Down, Hampshire, 



England 150 



Plate 46. 



A. Destruction of woodland of Pinv^ torrey- 

 ana by fire and erosion, and replace- 

 ment by chaparral, Del Mar, Cali- 

 fornia 162 



paob. 

 Plate 46. — Continued. 



B. Root-sprouting from the base of burned 



chaparral dominants, Quercus, Arcto- 

 stapylus, etc.. Mount Tamalpais, 

 California 162 



C. Destruction of plains climax, and inva- 



sion by woodland and scrub, bad 



lands, Crawford, Nebraska 162 



Plate 47. 



A. Deciduous forest climax, Acer-Fagus- 



hylion, Three Oaks, Michigan 168 



B. Plains grassland climax, Bulinlia-Boute- 



loua-poion, with OpurUia society. Big 



Bad Lands, South Dakota 168 



Plate 48. 



A. Montane climax forest of Pseudotsuga, 



Twin Sisters, Estes Park, Colorado . . 172 



B. Alpine climax forest of Picea engeU 



mannii and Abies lasiocarpa, Mount 



Blanoa, Colorado 172 



Plate 49. 



A. Pacific alpine climax forest of Abies lasio- 



carpa and Pinus murrayana, Crater 

 Lake, Oregon 176 



B. Pacific climax forest of Pseudotsuga, 



Thuja, and Tsuga, National Park Inn, 



Washington 176 



Plate 50. 



A. Desert scrub climax of Camegiea, Park- 



insonia, and Fouquieria, Santa Cata- 

 lina Mountains, Tucson, Arizona . . . 178 



B. Desert scrub climax of Artemisia tridevr- 



lata and woodland climax of Juni- 



perus-Pinus, La Sal, Utah 178 



Plate 51. 



A. Prisere alternes showing the serai stages 



from the bare diatom marsh to the 

 lodgepole subclimax, Firehole Basin, 

 Yellowstone Park 180 



B. Subsere alternes, due to the removal of 



sods for adobe houses, showing three 

 stages: (1) rushes, (2) salt-grass, 

 (3) Anem^psis, Albuquerque, New 



Mexico 180 



Plate 52. 



A. Hydrosere of Batrachium, Potamogeton, 



Nymphaea, Carex, etc., Lily Lake, 

 Estes Park, Colorado 182 



B. Xerosere of Lecidea, Parmelia, Ceratodon, 



Grimmia, etc.. Picture Rocks, Tuc- 

 son, Arizona 182 



Plate 53. Bisect of the halosere of Great 



Salt Lake, Tooele Valley, Utah 234 



Plate 54. 



A. Stase of TiXia am-ericaruj, buried by dune- 



sand and uncovered by wind erosion. 

 Dune Park, Indiana 292 



B. Stase of Pinus murrayana, due to de- 



struction and burial by travertine 

 terraces. Mammoth Hot Springs, 



Yellowstone Park 292 



Plate 55. 



A. Peat stase due to accumulation; birch 

 trunk between two peat layers, 

 "Burton Lake," Lancashire, Eng- 

 land 294 



