ILLUSTRATIONS xvii 



91. Head of Amber Sweet Sorghum 246 



92. Plant of Kafir Corn 247 



93. Non-saccharine Sorghums 247 



94. Sorghum Seeds 248 



95. Broom-corn Group of Sorghums 249 



96. Field of Selected Brown Kowliang 251 



97. Chart Showing Distribution of Potato Production in the World. . . . 256 

 98 Chart Showing the Distribution of Potato Production in the United 



States 258 



99. Drawing in Diagram of Potato Flower, and Mature Seed Balls. . . . 259 



100. Illustration of a Potato Plant, Showing Relation of the Above-ground 



Stem and Under-ground Stem 260 



101. Variety, Irish Cobbler, Representing the Early, Round, White- 



skinned Type 261 



102. Rural New Yorker, Representing the Oval-flattened Type of White- 



skinned Potatoes with Blue Sprouts 261 



103. Early Rose, Representing the Rose Group of Long, Pink or Red- 



skinned Potatoes with Rather Deep Eyes 262 



104. Russet Burbank, Representing the Medium Long Types of the Bur- 



bank Group ,263 



105. Illustration Showing the Internal Structure of a Potato Tuber, and 



Relation to Structure of a Stem 265 



106. Intensive Potato Culture on a Long Island Farm, Under the " Skin- 



ner System " of Irrigation 269 



107. Comparing Tubers Sprouted in Strong Light and in Darkness 273 



108. A Good Type of Cultivator. The Rows Have Already Been Ridged 



with a Killer 277 



109. A Large Potato Digger : 278 



110. A Dozen Plants, in a Good Field, Killed by the Disease Rhizoctonia. 280 



111. A Power Sprayer That Will Spray Seven Rows at One Time 281 



112. Potato Affected with the Rot, Resulting from Late Blight 282 



113. A Good Field of Potatoes .283 



114. A Single Sweet Potato from the Hot-bed, Showing Many Young 



Sprouts 288 



115. Sweet Potato Leaf and Blossom 289 



116. Some Commercial Types of Sweet Potatoes 290 



117. Map Showing Range of Production of Sweet Potatoes 291 



118. Sweet Potato Plant Ready to Set in Field 294 



119. Transplanting Machine 295 



120. Special Plow, Fitted with Two Rolling Coulters for Digging Sweet 



Potatoes 296 



121. Storage Houses 298 



122. Sweet Potato Affected with Black Rot, and Plant Affected with 



Same Disease 299 



123. Distribution of Forage Crops in United States 303 



124. Orchard-grass Representing a Typical Bunch Grass 310 



125. Plants Used in Mixture for Pasture on Poor Land 321 



126. A Student Identifying Clover Seed. . . 330 



127. Tripod Lens Used in Identifying Seeds 330 



128. Crimson Clover 330 



129. Alfalfa 331 



130. Yellow Trefoil 331 



131. White Clover 331 



132. Bokhara Clover 331 



133. Alsike Clover 332 



134. Red Clover 332 



135. Sainfoin . 332 



