INDEX AND GLOSSARY 



699 



Weeds, unconscious transfer by man, 



330. 



^Velwitschia, deep-rooted, 210 ; cor- 

 relation in, 218. 



Wheat, mummy, 334, as host of 

 Puccinia, 432 (Fig. 329) ; infection 

 by aecidium spores, 433 ; by 

 uredospores, 434 (Fig. 333) ; struc- 

 ture of grain, 658 (Figs. 503, 504) ; 

 analysis of, 660 ; origin of, 661. 



Whole-meal, 660. 



Wild-hyacinth (Scilla), 608. 



Willow (Salix), cuttings, 132 (Fig. 

 86) ; viability of seeds, 141 ; 

 flowers of, 619 (Figs. 444, 447). 



Willows (pollarded), flora of, 331. 



Wilting, 105. 



Wind, as pollinating agent, 301 ; its 

 use in dissemination of seeds, 



325- 

 Winter-kale (Brassica), analysis of, 



655 ; origin of, 654. 



Winter-spores, or buds (Teleuto- 



spores) of Puccinia, 433 (Fig. 



334) ; germination of, 435 (Fig. 



335)- 

 Wood-fibres, 59 (Fig. 38). 



Wood-parenchyma, 59 (Fig. 38). 



Wood-rush, 614 (Fig. 461). 



Wood-sorrel, movement in, 162. 



Woodwardia, sporophytic budding 



in, 494 (Fig- 3 8 6). 

 Working hypothesis, of evolution, 



339- 

 Wrought-iron, qualities of, 178. 



Xanthophyll, T17. 



Xanthoria, 428 (Fig. 326). 



Xerophytes, plants adapted for life 

 under conditions of drought, 208 ; 

 their characters, 209 ; succulence 

 of, 209 (Fig. 141) ; structural 

 modifications of, 210 (Fig. 142) ; 

 sunken stomata of, 210 (Fig. 142). 



Xylem, the woody region of the vascu- 

 lar strand, 45 (Fig. 23), 46 (Fig. 24). 



Yeast in fermentation, 136, 137, 393. 

 Yellow-flag (Iris), 609 (Fig. 458) ; 



stock of, 196 (Fig. 129). 

 Yellow-rattle (Rhinanthus), green 



root-parasite, 222 ; compare Fig. 



149. 

 Yew (Taxus), 527. 



Zea (Maize), vascular bundles of, 51 

 (Figs. 29, 31) ; analysis of grain, 

 660 ; origin of, 661. 



Zamia, 527 (Fig. 415). 



Zizyphus, straggling by stipules, 214 

 (Fig. 143, ii.), 345. 



Zoogloea, of Bacillus subtilis, 448 

 (Fig. 346). 



Zones of growth, 143 (Fig. 88). 



Zoospore, of Ulothrix, 365 (Fig. 

 270, of Oedogonium, 367 (Fig. 271). 



Zoosporangium, of Pythium, 404 

 (Fig. 303). 



Zoospore, a spore motile in water : 

 of Ulothrix, 365 (Fig. 270) ; of 

 Oedogonium, 367 (Fig. 271) ; of 

 Bulbochaete, 367 (Fig. 272) ; of 

 Vaucheria, 369 (Fig. 274) ; of 

 Potato Fungus, 408 (Fig. 308) ; in- 

 fection of Potato by, 408 (Fig. 309). 



Zygnemaceae, 372. 



Zygomorphic, lop-sided symmetry 

 within the flower, 274 (Fig. 199). 



Zygomycetes, 399, 401, 412. 



Zygospores, of Mucor, 399, 415 (Fig. 



3H)- 

 Zygote, the product of fusion of two 



gametes (syngamy) : of seed- 

 plants, 310, 315 (Fig. 234) ; of 

 Ferns, 503 (Fig. 396) ; of Spiro- 

 gyra, 373 (Fig. 277), 557. 

 Zymase, 129, 137. 



