PRACTICAL PROBLEMS IN BOTANY PRACTICAL PROBLEMS IN BOTANY BY WILFRED W. BOBBINS, Professor of Botany in the College of Agriculture of the University of California AND JEROME ISENBARGER Lecturer, Natural Science Loyola University, Chicago Sixth Printing NEW YORK JOHN WILEY SONS, INC. LONDON CHAPMAN HALL, LIMITED PREFACE It is the belief of the authors of this book that no subject con tributes more, when properly taught, to the attainment of the cardinal principles of secondary education than does biological science. It is the main province of this text to lay a foundation of fundamental principles which will enable pupils to develop an understanding of the significance of plant life which is such an important part of their environment. Moreover, the work in botany should be made practical in the sense that it should supply a basis of fact necessary to an understanding of principles, so that the student can use them in developing within himself a degree of social, civic, ethical, and esthetic efficiency. A practical course in botany should aid in developing an appreciation of the possibilities of improvement of the home environment through putting into practice a knowledge of the principles of plant growth. Window-plant culture, landscaping of home grounds, vegetable and flower gardening not only con tribute to the attractiveness of the home, but they also provide pleasant and profitable avocations as worthy use of leisure time. Also, knowledge of foods, bacteria, and the laws of sanitation, and the life out-of-doors occasioned by engaging in vocations and avocations along the lines of plant study and plant culture, both tend toward personal efficiency by making the person a healthier individual. Certain aims and . objectives have been set up. The problems and exercises are such as to be a direct aid in the attainment of these aims and objectives. The teacher who administers the course should not only have in mind the general objectives, but he should also recognize locally adapted specific objectives which should aid in determining points of special emphasis. Local con ditions which affect specific aims include dominant interests of pupils, community interests and needs, and availability of local resources, as woods and streams, greenhouses, parks, farms, v vi PREFACE health laboratories, landscaped homes, milk-pasteurizing plants, canneries, and facilities for sewage disposal. The problem involves learning activities which when properly directed by the teacher and carried out by the pupil will lead to the development of significant biological ideas and to the acquisi tion of the elements of scientific thinking. The course is organized as a series of problems and sub problems. It is intended that each problem shall lead pupils inductively to an understanding of important generalizations. The introduction of the book is an over-view of the entire course, and the introduction of each unit is an over-view of that unit. Provision is made for meeting individual differences by including suggested activities and additional exercises and problems which may be done by pupils who are able to finish the required work ahead of the majority of the class. The arrangement of the units is logical as it stands, but it is not intended as the best order under all conditions. Teachers who prefer a seasonal arrangement will find it possible to change the order of presentation of units to suit their requirements. A course beginning at mid-year will require an arrangement of units different from that which is best for a course beginning in the fall. Teachers are referred to The Teaching of Biology, by William E. Cole, published by D. Appleton-Century Company, for helpful suggestions regarding points of view in biology, laboratories, equipment, bibliographies, and materials. WILFRED W. ROBBINS September 9, 1935. JEROME ISENBARGER CONTENTS PAGE INTRODUCTION 2 UNIT I. ORGANIZATION AND COMPOSITION OF PLANTS PREVIEW OF THE UNIT 9 PROBLEM 1...