INDEX. 



5'3 



Willow family, 494 



Wind, 471 



Wintergreen, 499; leaf of, 43 



Witch-hazel, 49O 



WolfSa, 28 



Woodland formation, 470 



XerophytL-s, 467 



Xylem, 50, 52, 360, 361, 363 



Xylogcn, 92 



Xyridales, 493 



Yeast, 216; fermentation of, ii^,, 



116 

 Yucca, 480, 493 



Zamia, 313, 316, 457 



Zoogonidia, 143, 149, 178-184 



Zoospore, 149, 154 



Zygomycetes, 215 



Zygospore, 2, 138-140, 157, 160, 179, 



'180 

 Zygote (zy'gote), 138, 179 



