CONTENTS 7 



PROBLEM PAGE 



60. What do plants take out of the soil ? . 78 



61. How are root hairs able to take mineral matter out of the soil ? . . 79 



62. What are root tubercles and what is their use ? 79 



63. What is crop rotation and what is its use ? 80 



64. What roots are useful as food ? 80 



VII. Plant Growth and Nutrition — Plants Make Food . 84 



65. To prove that water is given off by a green plant .... 85 



66. Through which surface of a leaf does transpiration take place ? . .85 



67. To determine how the structure of a leaf fits it for the work it has to do 85 



68. To study the microscopic structure of a leaf 86 



69. To show the effect of light on green leaves 86 



70. To determine the relation of light to the presence of starch in a green 



leaf . 87 



71. Is a part of the air a factor in starch making in leaves ? . . .87 



72. The need of chlorophyll for starch making 88 



73. To consider the leaf as a manufactory . . . . . .88 



74. To show that a gas is given off as a waste product when green plants 



make starch 88 



VIII. Plant Growth and Nutrition — The Circulation and 



Final Uses of Food by Plants .... 91 



75. Groups of plants told by the structure of their stems .... 91 



76. To study the structure of a woody stem 92 



77. To prove that liquids rise through stems (Review) 93 



78. To find out through which part of a woody stem food passes down . 94 



79. How plants with special digestive organs get their nitrogenous food . 94 



IX. Our Forests, their Uses and the Necessity for their 



Protection ...... 96 



80. To determine how lumber is cut and how to rtcivnirp the cut in trim 96 



81. To determine some uses of stems 97 



82. To determine the value of certain woods 97 



83. Museum trip for study of woods . . . . . . . .98 



84. To identify common trees by the use of a key 99 



X. The Economic Relation of Green Plants to Man . 106 



85. To determine the economic importance of some green plants . . 106 



86. To learn to know some green plants harmful to man . . ... 107 



XI. Plants without Chlorophyll in their Relation to Man 110 



87. To determine the relation of fungi to the destruction of certain trees . Ill 



88. To determine the conditions favorable for the growth of mold . .112 



89. To study the structure of bread mold 112 



