AH INTRODUCTION TO PLANT BIOLOGY 67 



scopic size, and all are in general appearance quite different 

 from the familiar flowering plants ; but in many important 

 respects there is much similarity. It is therefore possible by 

 a careful study of some common flowering plant to learn 

 many interesting and useful facts which are common to 

 plants in general. 



The common bean plant has been selected for this begin- 

 ning study, because it can be conveniently grown from seed 

 planted in gardens or in boxes in the schoolroom, and be- 

 cause the seeds themselves are large and easy to study. 

 Many other plants might have been selected for these lessons ; 

 in fact, the following account of the structure and life of the 

 bean plant will serve as a general guide for the study of 

 any flowering plants, provided the student has specimens 

 of the plants and uses this book chiefly as a guide to examin- 

 ing the actual plants. 



STRUCTURE OF A BEAN PLANT* 



66. Organs of the Plant. If we examine a fully de- 

 veloped bean plant, we notice first that it has several parts 

 or organs. These are roots, stem with its branches, buds, 

 leaves, flowers, and sometimes fruits with seeds. We call 

 these organs, because an organ of a plant or of an animal is a 

 structure for doing a particular work ; for example, lungs are 

 organs for breathing. The roots, stem, leaves, and flowers are 

 the plant's organs for taking food, for breathing, for reproduc- 

 ing in short, for carrying on all the life-activities which 

 in an earlier lesson ( 29) we found to be characteristic of 

 all living things. How can the organs of the plant perform 



* The most prominent part of the subject-matter of this division is a 

 description of structure ; but, as in the case of the frog, some general reference 

 to the work of the various organs has been coupled with the first study of 

 their structure. A later division of this chapter presents a more careful 

 survey of the life-activities of a plant in a way similar to the lessons on the 

 work of the organs of the frog in Chapter IV. 



