146 



BOTANY 



A mesophytic condition. A valley in central New York. 



of the ground is frozen, thus preventing water from finding its 

 way below the surface. 



Plant Societies. Field Work. — Any boy or girl who has access to a 

 vacant lot or city park can easily see that plants group themselves into 

 societies. Certain plants live together because they are adapted to meet 

 certain conditions. Societies of plants exist along the dusty edge of the 

 roadside, under the trees of the forest, along the edge of the brook, in a 

 swamp or a pond. It should be the aim of the field trips to learn the names 

 of plants which thus associate themselves and the conditions under which 

 they Uve, and especially their adaptations to the given conditions.^ 



Other Factors. — It is a matter of common knowledge that plants in 

 different regions of the earth differ greatly from one another in shape, size, 

 and general appearance. If we study the causes for these changes, it be- 

 comes evident that the very same factors which govern hydrophytic, xero- 

 phytic, and mesophytic conditions determine, at least in part, the habits of 

 the plants growing in a given region — be it in the tropics or arctic regions. 

 But in addition to water supply the factors of temperature, light, soil, wind, 

 etc., all play important parts in determining the form and structure of a plant. 



^ Suggestions for such excvirsions are found in Andrews, Botany all the Year 

 Round, Lloyd and Bigelow, The Teaching of Biology, Ganong, The Teaching Botanist, 

 and many other books. A convenient form of excursion is found in Himter and 

 Valentine, Manual, page 202. 



