i8o 



BOTANY OF THE LIVING PLANT 



Woodwardia, sporophytic budding in, 



336 (Fig. 277). 

 Wrought-iron, qualities of, 146. 



Xantlioria, 438 (Fig. 372). 



Xerophytes, plants adapted for life 

 under conditions of drou.ght, 96 

 175 ; thorny character of, 176 

 succulence of, 176 (Fig. 132) 

 glandular hairs of, 177 ; sunken- 

 stomata of. 177 (Fig. 133). 



Xylem, the woody region of the 

 vascular strand, 37 (Fig. 23), 39 

 (Fig. 24). 



Yellow-flag (Iris), 496 (Fig. 400). 

 Yellow-rattle (Rhinanthus), green 



root-parasite, i8g, 193. 

 Yew (Taxus), 302. 



Zea (Maize), \'ascular bundles of, 44 

 (Figs. 30, 31) ; analysis of grain, 

 547 : origin of, 548. 



Zizyphus, straggling by stipules, iSi 



(Fig. 134, ii.). 

 Zoogloea, of Bacillus subtilis, 458 



(Fig. 391). 

 Zoosporangium. of Pvthiuni, 415 



(Fig. 351)- 

 Zoospore, a spore motile in water : 



of Ulothrix, 392 ; of Oedogonium 



(Fig. 331) ; of Bulbochaete (Fig. 



332) ; of Vaucheria (Fig. 334) ; 



of Pythium, 415 (Fig. 351) ; of 



Potato-Fungus, 418 (Fig. 353) ; 



infection of Potato by, 419 (Fig. 



356)- 

 Zygnemaceac, 39S. 

 Zygomorphic, lop-sided 



within the flower, 240 



189). 

 Zygomycetes, 410, 412, 42 

 Zygosporeae, 454. 

 Zygospores, 410 (Fig. 345) 



426. 

 Zygote, the product of fusion of two 



gametes (syngamy) ; of seed-plants, 



271 (Fig. 215), 274 ; of Ferns, 345 ; 



of Oedogonium, 394. 



symmetry 

 (Figs. I S3, 



of ilucor, 



