LABORATORY AND FIELD WORK 271 



4. To compare a psammosere with a lithosere in the same climatic 

 region. 



5. To determine the successional significance of zonation. 

 Phenology.— As a general rule phenological studies are not well 



adapted for single field exercises but they furnish an abundance of 

 excellent problems for individual students or groups of students to 

 carry on throughout a field season. 



Suggested Problems 



1 . To make a study of the seasonal succession of flowers in a local 

 association. 



2. To make a comparative phenological record of all species of 

 maple that are available. 



3. To make a comparative study of the time of leaf development 

 on the various species of trees on the campus or in a local wood-lot. 



4. To make a comparative study of the time of leaf fall on the 

 above trees. 



5. To make a comparative study of the time of ripening of fruits 

 on the plants of a local association. 



REFERENCES 



Bates, Carlos G., and Zon, Raphael: Research Methods in the Study of 

 Forest Environment, U. S. Dept. Agric. Bull., 1059, 208, 1922. 



Clements, Frederic E., and Goldsmith, Glen W. : The Phj^tometer Method 

 in Ecology; the Plant and Community as Instruments, Carnegie Inst. Wash- 

 ington Publ., 256, III + 106 p., 11 pL, 45 fig., 1924. 



Tansley, a. G., and Chipp, T. F.: Aims and Methods in the Study of Vege- 

 tation, The British Empire Vegetation Committee and the Crown Agents 

 for the Colonies, London, 15 -|- 384 p., 62 fig., 1926. 



