PREFACE 



The course of work followed in this book is directed, 

 in the main, to the establishment of the fundamental 

 principles of Plant Physiology. Plant Morphology 

 receives a less extended treatment ; but this aspect 

 of the subject is freely introduced in the discussion 

 of Plant Ecology, i. e. the relation of the structure 

 and functions of plants to their habitat. More space 

 has been devoted to Ecology than is usual in an ele- 

 mentary text-book, but the Author believes that this 

 aspect of plant life gives to field work a more definite 

 aim, and broadens the outlook of the student by linking 

 up Botany with the study of climate, geology, and 

 topography. Similarly, to avoid the weariness of 

 lessons dealing merely with the comparison of forms, 

 the Author has throughout treated the forms of roots, 

 stems, and leaves in relation to their functions and to 

 the habitat of the plant. 



The plants selected for study are common species : 

 nearly all of them can be obtained from the fields, 

 hedgerows, and gardens, and it is expected that speci- 

 mens will be in the hands of students using the book. 

 The experiments suggested are usually so simple and 

 require such inexpensive apparatus that every pupil 

 in a class ought to be able to do them. Details of struc- 

 ture occasionally require the compound microscope ; 

 where this instrument is not available, a general idea 

 can be obtained by the aid of a pocket lens. It is hoped 



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