31] Soziologische Pflanzengeographie. 253 



(2) Quadrat methods. 



(1) List quadrats. 



(2) Chart quadrats. 



(3) Permanent quadrats. 



(4) Denuded quadrats. 



3. The Transect. 



4. The ]\Iigration Circle. 

 6. Photography. 



6. Cartography. 



7. Formation Herbaria. 



Chapter IV. Experimental Ecology. 



1. Concept and Purpose. 



2. Scope 



(1) Coefficients of adjustment: hydroharmosis. photoharmosis. 



(2) Course and measurement of adaptation. 



(3) Oontinuous and discontinuous Variation. 



(4) Ecological tests in taxonomy. 



3. Field Experiment. 



(1) Historical. 



(2) Methods. 



(a) Normal structure of habitat, ecads, and formation. 



(b) Determinate modification of the habitat: (1) by increasing or 

 decreasing water content (2) by varying the light intensity (3) 

 by changing the salt content. 



(c) Record of structural changes in ecad and formation. 



(d) Change of habitat by transfer of plant or seed, with reference 

 to direct factors, water content, and light, or indirect, soil and 

 altitude. 



(e) Culture of related species in the same habitat. 



(f) Artificial succession, by Clearing, burning, flooding. etc. 



4. Control Experiment. 



(1) Methods of equalization and control. 



(2) Doctrine of extremes. 



(3) Series of experiments. 



(4) Factor and plant records. 



6. Comparative Morphology and Histology of Field and Control Forms. 



(1) Endemie and polydemic species. 



(2) Artificial ecads. 



(3) Control forms. 



(4) Ancestry and habitat. 

 6. Competition Cultures. 



(1) The Factors in competition. 



(2) Methods. 



(3) Simple cultures. 



(4) Mixed cultures. 



(5) Layered cultures. 

 Bibliography. 



99a. Smith, A. The botany of a place of waste ground. (Nature 

 Study, XIII. 1904. p. 181—183.) 



