INDEX 



89 



Wind and soil— Continued 



blowouts, 111, 112 



buried forest, 112, 114 



during droughts, 110, 112 



loess, 110, 112-113 



sand dunes, 111, 113 

 Wind, coastal, night and day breezes, 



98 

 Wind, in mountains 



cold air drainage, 98 



valley breezes, 98 

 Wind, physical effects 



flagform, 106 



windthrow, 104, 105 

 Wind, transportation 



of disseminules, 108-112 



of pollen, 107-108 

 Witches brooms, 191-192 



X 



Xanthium canadense, 199 



Xerarch succession, 213-218-219-221 



arctic, 238-239 

 Xeric habitats and leaf structure, 139 

 Xeromorphism 



in halophytes, 184 



transpiration, 184 



Yucca 290 



brevifolia, 287, 288 



Zephyranthes atamasco, 68 

 Zones of vegetation (see Vegeta- 

 tion Zones) 



