43 6 



Introduction to Botany. 



Virginia creeper, 73, 136 ; effect of darkness 

 on, 118 ; experiment with tendrils of, 103. 

 Viscid disk, 190. 



Walnut, 20T. 



Water, cross pollination by, 178 ; demonstra- 

 tion of region of rise of, 29, 53 ; current, 

 diagram to show, 99 ; effect of submerg- 

 ence in, 807 ; importance of, 87 ; effect of 

 scarcity of, 306. 



Water lily, 140. 



Water plants, roots of, 40. 



Water supply, 306. 



Wild cucumber, tendrils of, 103. 



Willow, 177 ; adventitious roots of, 44 ; Cre- 

 taceous, 355. 



Wind, adaptation to, 177. 



Winds, effect of, 814. 



Winter buds, protection afforded, 67. 

 Wood, use of, 56. 



Xerophytes, 319 ; character of, 322 ; North 



American, 321 ; origin of, 326. 

 Xerophytic conditions, 320. 

 Xylem, diagram to show, 58, 91 ; function of, 



51. 



Yeast, culture of, 256 ; in alcoholic fermenta- 

 tion, 263 ; in bread-making, 262 ; nature 

 of, 261 ; reproduction of, 262. ; 



Yucca, 147 ; arboreus, 321 ; cross pollination 

 of, 196-201 ; in twilight, 198. 



Zilla spinosa, 845. 



Zygophyllum cornutum, 322, 328. 



