INDEX 



545 



Water, absorption by roots, 7-9 



Water, amount transpired, 18 



Water, movement of, 9, 11, 80 



Water ferns, 290*, 291* 



Water lily, flower of, 105* 



Water molds, *21 7-219 



Water plants, *479-481 



Water plants, leaves of, 67*, 68 



Water roots, 30 



Water storage, 74, 75 



Water supply, 169, 174, 177, 205, 



206 



Water supply in soils, 439-441 

 Webber, H. J., 430 

 Weeds, *465-476 

 Weeds, aquatic, 471 

 Weeds, classes of, 465, 466 

 Weeds, dissemination of, 472-474 

 Weeds, injuries caused by, 470-472 

 Weeds, origin of, 473 

 Weeds, prevention of, 475, 476 

 Weeds, success of, 466-468 

 Wheat, hybridizing of, 428*, 429* 

 Wheat breeding, 413-417 

 Wheat culture, 457 

 Wheat grain, section of, 138*, 139* 

 Wheat rust, *242-245 

 White pine, distribution map, 504* 

 Wild ginger, 58* 

 Williams, C. G., 423 

 Willow, flowers of, 106*, 107* 

 Wilting of corn leaves, 6*, 20 

 Wind pollination, 120 



Winged fruits and seeds, 150*, 151* 



Winter buds, 90* 



Winter spores of wheat, rust, *243- 



245 



Wood, coniferous, 304, 390* 

 Wood, fuel value of, 395 

 Wood, physical properties of, 392- 



395 

 Wood, structural advantages of, 394, 



395 

 Wood, structure of, 45*, 46*, 48*, 



*50-53 



Wood, tracheids of, 48*, 391 

 Wood fibers, 48 



Wood sections, 50*, 53*, *390-392 

 Wood sorrel, leaf positions of, 65* 

 Woodbine, 61* 



Xerophytes, 480, *481-487 



Yarrow, head and flower of, 369* 



Yeast, 232*, 233 



Yellow fever, 163 



Yellow pond lily, transitions between 



petals and stamens of, 105* 

 Yucca, 509* 

 Yucca, pollination of, 127, 128*, 129* 



Zamia, 317 

 Zoospores, 191 

 Zygnema, 204* 

 Zygomorphic, 108, 109* 

 Zygospore, 194 



