INDEX 



555 



Uridinales, 260-264* 



Uroglena, 170*, 171, 178 



Uses of the components of the stem, 



72 



Usnia, 257* 

 Ustilaginales, 259* 

 Ustilago, 259* 



Vacuole, pulsating, 158* 

 Variation, 496, 497, 499 

 Variety, 500, 503, 504, 506-508, 



512* 



Vaucheria, 197-200* 

 Vegetable physiology, 2 

 Vegetation, alpine, 484-487*, 493 

 Vegetation, arctic, 484* 

 Vegetation, regions of, 481 

 Vegetation, temperate, 482. 483 

 Vegetation, tropical, 481, 482* 

 Vegetative organs, 15 

 Vein, 89*, 106* 

 Venation, 89*, 106* 

 Venus flytrap, 411, 412* 

 Vernation, 85, 86* 

 Vertically placed leaves, 100*, 101* 

 Vessel, 61*, 72 

 Volvox, 182-184* 



Walking fern, 310* 



Water, absorption by roots, 28 



Water, amount transpired, 119, 



120 



Water bloom, 177 

 Water, excretion of, 115-120 

 Water fern, 320* 

 Water lily, flower of, 130*, 139* 

 Water molds, 242-244* 

 Water, movement of, 28-30*, 73-78*, 



105, 106*, 116-120 

 Water roots, 20 



Water supply, pollution of, 171, 178 

 Weapons of plants, 416-419* 

 Wedge-shaped, App. 1 



Weeds, 452, 453 



Wheat grain, section of, 9* 



Wheat, hybridizing of, 512*, 513 



Wheat rust, 260-263* 



Wheat, selection among, 507-509 



Wheel-shaped, App. II 



Whorl, 123* 



Willow, adventitious buds of, 87 



Willow, arctic, 484* 



Willow, flowers of, 124* 



Wind pollination, 421* 



Winged fruits and seeds, 439-441*, 



442* 



Wings, 125* 

 Winter buds, 80 



Winter spores of wheat, 260*, 261 

 Witches' broom, 264 

 Wood cell, 25*, 61*, 62*. 72. 7-".* 

 Wood, coniferous, 366*, 367 

 Wood of linden, 66* 

 Wood parenchyma, 64 

 AVood sections, 59-68* 

 Wood, structure of, 61*, 63*, 66* 



Xenia, 384 n. 



Xerophytes, 459, 462-466*, 482, 485 



Xerophytic leaves, 465*. 466* 



Xylaria, 252 



Xylem, 311, 312*, 366*, 367 



Yarrow, head of, 135* 

 Yeast, 238*, 239 

 Yucca, 495 



Zamia, 360*, 362* 

 Zonation, 475-478*, Plate X 

 Zones, 475-478*, Plate X 

 Zoosporangiurn, 204 

 Zoospores, 185*, 204 

 Zygnema, 194* 

 Zygomorphic, 125 



Zygospore, 167, 182, 185*, 186, 193*, 

 194*, 204, 206* 



