INDEX 



493 



Ulmaceae, 405. 

 Ulmus americana, 405. 

 Ulothrix zonata, 222. 

 Unit characters, 461, 477. 

 Uredospores, 282-284. 

 Uromyces caryophyllinus, 1 29. 

 Urticaceae, 404. 

 Usnea barbata, 273. 

 Ustilago avenae, 277. 

 Ustilago hordei, 277, 278. 

 Ustilago tritici, 277. 

 Ustilago zeae, 276, 277. 



Vacciniaceae, 415. 

 Vaccinium macrocarpon, 416. 

 Vaccinium oxycoccus, 416. 

 Vaccinium vitisidaea, 416. 

 Variation in plants, how produced, 



467. 

 Varieties, production of new, 467; 



objects in, 472. 

 Vaucheria, 226-228, 230, 301. 

 Veil, of mushroom, 294. 

 Veins, of leaf, 71, 72. 

 Venus flytrap, 81, 88. 

 Veratrum viride, 69, 76. 

 Vetch, root tubercles of, 121. 

 Vibrio, 135, 245. 

 Viburnum opulus, 172. 

 Violet seed, 185. 

 Viscum ablum, 128. 

 Vitis-Idaea vitisidaea, 416. 

 Volva, 295. 



Walking fern, 42, 327. 



Walnut, 190, 403. 



Walnut order, 403. 



Wandering Jew, 28, 29. 



Water hyacinth, 30. 



Water molds, 254-256. 



Water net, 221, 229. 



Water storage by desert plants, 449. 



Watermelon, 419. 



Wheat, 393-395- 



Wheat grain, section of, 14. 



Wheat rust, 280-287; races of, 285; 



history of, 286; prevention of, 287. 

 Wheat smut, loose, 277; stinking, 



278, 279. 



White rust, 256-259. 

 Willow, buds and shoots of, 68. 

 Willow mildew, 262. 

 Willow order, 403. 

 Wind, 422, 423. 

 Wintergreen, 415. 

 Witches' broom, 280. 

 Wood-destroying fungi, 131. 

 Wood, porosity of, 59, 60. 

 Woody portion of vascular bundle, 



3i, 53-58. f 

 Wound parasite, 131. 



Xanthoxylum, 411. 

 Xerophytes, 426. 

 Xylem, 31, 54-58. 



Yeast, fermentation by, 114; growth, 



115, 268. 

 Yew, American, staminate cones of, 



359- 

 Yucca, pollination of, 171. 



Zamia, 369-371, 401. 



Zamia, female gamete plant, 370; 



egg cases, 371. 



Zamia, germination of pollen, 370. 

 Zamia, male gamete plant, 370. 

 Zea mays, 397. 



Zonal distribution of plants, 453. 

 Zob'gonidia, 222, 223, 225. 

 Zobspores, 222, 225, 236, 254. 

 Zygospore, 216-219, 221, 251-253. 

 Zygnema, 219. 

 Zygospores, 216, 217-219, 221, 222, 



251, 252. 

 Zygote, 217, 219, 224, 325, 342, 374, 



39i. 

 Zymase, 135. 



