114 THE BRACKEN-FERN. 



ii. The imbedded venter, from which 

 iii. The recurved neck extends, 

 iv. The egg, ventral canal, and neck canal cells, 

 v. Draw. 



VI. THE YOUNG SPOROPHYTE. 



By means of sections made as for 2. b. ii. study early stages 

 in the development of the sporophyte. Observe: 



1. Recently fertilized eggs, in which the first division wall 

 has appeared. Note its direction and how it divides the 

 oospore. Draw. 



2. The direction of the second division walls, and the result- 

 ing quadrants. Each of these quadrants forms a definite 

 organ of the young sporophyte embryo, foot, stem, leaf, or 

 root. Draw. 



3. Some older sporophyte embryos in which some of the em- 

 bryonic organs are discernible. Draw. 



4. With some fresh material search for specimens in which 

 the first leaf of the young sporophyte is emerging from the 

 notch of the gametophyte, while the real stem is beginning 

 to grow downward, and the foot still holds the young plant 

 to the old gametophyte. Draw. 



ANNOTATIONS. 



A striking difference between Pteris and any Bryophyte 

 studied is seen in the fact that in ferns the mature gameto- 

 phyte and sporophyte generations are able to live inde- 

 pendent of one another. Each has organs relating it to the 

 surrounding medium, and each has chlorophyll by means 

 of which it can manufacture food from what it can absorb. 

 The gametophyte is for a brief time dependent upon 

 food stored in the spore that forms it, and the sporophyte 



