GLOSSARY 



421 



whorled generally pertaining to three or more leaves at 



a single node. 

 woodland a somewhat open growth of trees or shrubs, 



not as densely spaced as in a forest or as loosely spaced 



as in a savanna. 

 xerorch pertaining to a sere beginning on a dry substrate, 



especially on bare rock. 



xerophyte a plant adapted to dry environmental condi- 

 tions. 



xylem a woody tissue in vascular plant veins that conducts 

 water and water solutions. 



zoology the study of animals. 



zygote a fertilized egg; a cell resulting from the fusion of 

 two parental gametes. 



