xviii List of Illustrations 



FIGURE PAGE 



85. Bugbane (Cimicifuga racemosa} . . . -.. . 275 



86. Blossom of flowering raspberry (Rubus odoratus) . . 276 



87. Squash flowers of each sex . . . . . . 277 



88. Flowers of clematis ( Clematis virginiana) . . . . 278 



89. Tobacco flowers, showing the parts of the flower, a bud 



ready to be emasculated, and an emasculated subject . 282 



90. Zinnia flowers . . . ... . .283 



91. Instruments used in pollinating flowers . . . . 284 



92. Ladle for pollinating house tomatoes . . . . 285 



93. Bag for covering the flowers . . . . . .286 



94. Fuchsias, showing the stamens and pistils, and a bud ready 



to be emasculated . . . ... . . 287 



95. Fuchsia flower emasculated . . '..'. - . . . 288 



96. Fuchsia flower tied up after emasculation i 289 



97. Tomato and quince . . . . . . 290 



98. Pollinating kit . . . ..;.'"..'.; . . 291 



99. Pollinating kit ". . . .292 



100. Main building of Seed Association, offices of Swedish Com- 

 pany (photo by Newman) . . , ' v . . 307 



10L Gardens at Luther Burbank's . . . 319 



102. Some of Burbank's frames and garden beds . . . . 320 



103. Spineless and spine-bearing cacti at Burbank's . . . 322 



104. A specimen herbarium sheet, showing variations in the 



leaves of the mulberry . . . . . . . . 395 



105. A specimen herbarium sheet, showing differences between 



two leaves of the horse radish . .:,....... . 396 



106. A specimen herbarium sheet, showing variations in leaves 



of the Persian lilac , . 398 



107. A specimen herbarium sheet, showing variations in leaves 



of the blackberry 400 



108. A common form of ragweed . . . . . .421 



109. Another form of ragweed . 422 



110. Demonstration of allelomorphism and of complete dominance 431 



111. Demonstration of presence and absence hypothesis and of 



intermediacy . . . . . . ... 432 



112. Demonstration of the presence of an inhibitor factor . . 434 



113. Explanation of so-called " dominance and absence " . . 436 



