vi Pretace 



general course in botany that presents and organizes the more 

 important facts of plant physiology, morphology, ecology, and 

 economics is interesting to pupils of high school age and is 

 valuable to any one who later engages in the growing of 

 plants. The fundamental aim of this text, therefore, is to give 

 the pupil an understanding of how a plant lives and is affected 

 by its environment. The nutrition of the plant is the central 

 theme. Sufficient anatomy and morphology have been intro- 

 duced to make possible a discussion of the important plant 

 processes, including reproduction. The environment of 

 plants and their adjustments to various environmental fac- 

 tors have been discussed because a knowledge of these subjects 

 is essential to an understanding of many agricultural practices. 

 Attention is called to the uses that are made of plants and 

 plant materials and to the apphcations of botanical prin- 

 ciples in plant production in order that the economic im- 

 portance of plants and of a knowledge of plant Ufe may be 

 evident. In the final chapter an attempt is made to give 

 the pupil an understanding of what is meant by the term 

 "evolution" — to present a definition rather than a discussion. 

 The most valuable part of any course in botany is the study 

 of plants in the field and laboratory. It is through the work 

 with the plants themselves that the teacher has the best 

 opportunity to give pupils the insight into plant life that will 

 justify the expenditure of their time and energy on the course. 

 The laboratory work has been fairly well standardized in 

 secondary schools, and the methods of handling classes are 

 well known. This is not true of field work, although it is 

 no more difficult than laboratory work and is no less im- 

 portant. Two methods of conducting field observation have 

 been eminently successful. One is to take the class into the 



