LIST OF ILLUSTRATIONS 



FIGURE PAGE 



62. Raceme of Barberry . . . 125 



63. Panicle of Grass 126 



64. Head of Clover 126 



65. Head of Wild Lettuce 126 



66. Flowers of Barberry 127 



67-68. Flowers of Tomato 127 



69. Flower of Bean 127 



70. Aconite Flower 128 



71. Larkspur Flower 128 



72. Strawberry Flower 128 



73. Rose Flower 129 



74. Pollen Grains of Various Types 129 



75. Different Stages of Pollen Grains 130 



76. Fertilization in Cotton Plant 131 



77. Carpels of Indian Mallow 131 



78. Follicle of Larkspur 131 



79. Castor Oil Bean 131 



80. Bean Seed 131 



81. Cotyledons of Bean Plant 132 



82-83. Germinating Pea 133 



84. Squash Seed Germinating 134 



85. Cross-Section of Buckwheat Seed 134 



86. Cross-Section of Date Seed 134 



87. Longitudinal Section of Kernel of Corn 134 



88. Common Brake 138 



89. Smooth Crab Grass 140 



90. Green Foxtail 144 



91. Muhlenbergia racemosa 148 



92. Crowfoot Grass 150 



93. Quack Grass 154 



94. Little Barley 155 



94a. Plain Wild Barley 156 



95. Northern Nut Grass 158 



96. Slender Rush 159 



97. Common Nettle 161 



97a. Sour Dock 163 



98. Dooryard Weed * 165 



99. Smartweed 166 



100. Pennsylvania Smartweed 167 



101. Slender Smartweed 167 



102. Winged Pigweed 168 



103. Goosefoot 169 



104. Russian Thistle 170 



105. Orach 171 



106. Prostrate Pigweed 172 



107. Wild Four o'Clock 173 



108. Chickweed 174 



109. Evening Catchfly 175 



110. Corn Cockle 176 



111. Cow-Herb 177 



112. Purslane 178 



113. Crowfoot 179 



114. Pennycress 180 



115. Pepper Grass 1! 



1 16. Common Mustard 182 



117. Tumbling Mustard 183 



118. Stinkweed 185 



119. Five Finger 186 



120. Yellow Sweet Clover 189 



121. Black Medick 190 



122. Alfllaria 192 



123. Caltrop '193 



124. Spotted Spurge 194 



125. Creeping Spurge 195 



126. Spurge 196 



