INDEX. 
Vernation, 82, 83. 
Vertically placed leaves, 99, 100. 
Vessel, 31, 53, 59. 
Water, absorption by roots, 54-37. 
Water, amount transpired, 113-116. 
Water, excretion of, 125, 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, 28. 
Wheel-shaped, 147. 
275 
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. 
Wood-cell, 57, 58. 
Wood of linden, 54. 
Wood, structure of, 52-64. 
Yeast, study of, 226-230. 
Zoospores, 221. 
Zygospores, 223. 
