428 



INDEX. 



Weight, loss of 173 

 Welwitschia 140 

 Willow, fruit 365; leaf 127 

 Wind, distributing seeds 363; 



distributing spores 356; effect 



on form 313 

 Wings to fruits 364 

 Wintergreen, fruit 302, 304 

 Wheat, flower 258 ; geotropic 



stem 200; seedling 118 

 Wood, in root 71; secondary 113 



Xanthium, fruit 367 



Xerophytes 311, 318 

 Xylem bundles, of root 72; sec 

 ondary 109 



Yarrow, inflorescence 257 



Yeast, beer 40 



Yew ovule and fruit 239 



Zamia, flower 233 

 Zea, stem bundles 107 

 Zoospores 147, 212 

 Zygnema 20, 401 



