INDEX. 



275 



Vernation, 82, 83. 



Vertically placed leaves, 99, 100. 



Vessel, 31, 53, 59. 



Water, absorption by roots, 34-37. 

 Water, amount transpired, 113-116. 

 AYater, excretion of, 123, 124. 

 Water, movement of, 66, 68-72. 

 Water roots, 28. 

 Weapons of plants, 208-210. 

 Weather, protection from, 175, 176, 



205-207. 

 Wedge-shaped, 85. 

 Weeds, 197-199. 

 Weeds, study of, 198. 

 Wheat-grain, section of, 23. 

 Wheel-shaped, 147. 



Whorled, arranged in a circle 

 around the stem; for example, 

 leaves borne three or more at a 

 node. 



Willow, Arctic, 206, 207. 



Willow, adventitious buds of, 84. 



Wilting, 70, 



Wind-fertilization, 160, 161. 



Winged fruits, 188. 



AVood-cell, 57, 58. 



Wood of linden, 54. 



Wood, structure of, 52-64. 



Yeast, study of, 226-230. 



Zoospores, 221. 

 Zygospores, 223. 



