HEREDITY AND EVOLUTION 

 IN PLANTS 



CHAPTER I 

 LIFE HISTORY OF A FERN 



1. Life History. Every plant, in the course of its ex- 

 istence, passes through a series of changes in orderly 



FIG. i. A fern (Anisosorus hirsutus), showing portion of the stem above 



ground. 



sequence. Like an animal, every plant begins life as a 

 smgle cell, the egg, or the equivalent of an egg. Except 

 in some of the lower forms, the egg develops into an 



