228 INDEX 



Variation: alternative, 151 ; com- Vries, Hugo de, 11, 16, 22, 35, 38, 49, 



plexity, II ; continuous, discontinu- 57, 178, 182, 186 



ous, 17, 150, 153, 185, 187 ; index 



of, 30 ; meristic, 69 ; parallel, 195 ; 



plasticity, 9 ; substantive, 69 ; W 



under cultivation or domestication, 



i-j Wallace, 31 



Variation steps, 178 ; gradation, 184 ; Wasteels, 178, 183 



methods for the discovery of, 192 ; Weiss, F. E., vii. 69 



paraUel, 196 ; plasticity, 184 ; re- Weldon, W. F. R., 31 



lation with mean value, 176, 181 ; West, G. S.; 78, 83, 84, 93 



relation with phyUotaxis, 190 ; re- Wheat, 177 



lation with symmetry, 180 ; selec- Wille, N.; 97 



tion, 186 ; specific difference, 187 

 Varieties, 11, 15 ^ 



Vernon, 28, 182, 186, 195, 215 



Verschaffelt, E., 107. 178 Xylem, 112 



Vertebrates, 97 



VexUlary marks, 98, 108 Z 



Viola, 46, 194 



Vitis, 16 Zenith-Nadir, iio 



Volv'ox, 83 Zygnema, 70 



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