CHAPTER IV 

 SEASONAL ASPECTS OF PLANTS 



The succession of the seasons and the changes in plants and landscapes 

 associated with them are familiar to everyone who has lived in the tem- 

 perate zone. Even in the tropics there are but few localities in which 

 seasonal changes in weather and in plants do not occur. 



Changes in plants during the vear have always attracted attention, 

 even of primitive men. They have inspired much prose and poetry, as 

 well as scientific study and description. Explanations for their occurrence 

 were proposed so far back in the history of the human race that they 

 became an important part of mythology and folklore. Even today news- 

 papers and magazines frequently contain stories that are merely new 

 versions of these ancient myths which ascribed supernatural and mys- 

 terious powers of foresight to plants and animals alike. 



The changes that occur in the form and appearance and in the relative 

 abundance of different species from season to season may be seen in the 

 lawns, pastures, cultivated fields, and forests of your own community. 

 An accurate account — a diary — of such observations over a period of a 

 few years would include many valuable botanical data. This is another 

 way in which the studv of plants may be approached. 



Many seasonal phenomena may be studied best as individual prob- 

 lems during appropriate seasons when the material is abundant and 

 observations may be made over extended periods of time. As an aid to 

 such preliminary observations, certain facts about seasonal aspects of 

 plants have been brought together in this chapter. Data helpful in further 

 observations and interpretations are included in many of the subsequent 

 chapters. 



There are such great differences in the behavior of individual species 

 that few generalizations apply equally to all kinds of plants. Some of 

 the questions and problems that are sure to arise from your own pre- 

 liminary observations may be solved by further study or by well-planned 

 simple experiments. Let us begin with plants in autumn when most 

 courses in botany begin, and, by following the cycle of the seasons, con- 



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