380 
Water, excretion of, 133-135. 
Water, movement of, 78-81. 
Water, relation to germination, 8. 
Waiter roots, 31, 32. 
Water-lily, white, insertion of floral 
organs, *156. 
Water-lily, white, transitions from 
petals to stamens in, *160. 
‘Weapons of plants, 123-125*. 
Wedge-shaped, App. I, *355. 
Weeds, 200, 201. . 
Wheat-breeding, 314-316. 
Wheat-grain, section of, *17. 
Wheat-rust, type study, 255-259*. 
Wheel-shaped, *152. 
Willow, adventitious buds of, 95. 
Willow, flowers of, 150, *151. 
Wind-pollination, 168, 169. 
ESSENTIALS OF BOTANY 
Windsor bean seedling, *6. 
Winged fruits, *187. 
Wings, *150. 
Wood of linden, *73. 
Wood sections, *70, *73. 
Wood, structure of, *73, 74. 
Wood, varieties of. See Timber. 
Wood-cell, *69, *70. 
Work of leaf, 136. 
Xerophytes, 114-118*. 
Yarrow, head of, App. I, #359. 
Yeast fungi, 244-246*. 
Yucca, pollination of, *176, 177. 
Zoospores, *226. 
Zygospores, *221, #248, 
