PRACTICAL WORK. NO. IX. 215 



ing developing spores and some before this stage, just 

 shewing the columella. 



vi. Sketch a sporangium that has burst, shewing 

 a. the columella, to which some spores may be found 



adhering ; 



6. the remains of the wall of the sporangium at the 



base of the columella : 6 is known as the collar. 



vii. A series of sketches should be made from speci- 

 mens shewing stages in the formation of the zygospore by 

 the conjugation of branches from the hyphse. 



No. IX. 



THE FERN. 



i. Make a sketch of a part of a plant of Pteris 

 aquilina, shewing 

 a. the rhizome ; 

 6. its growing point ; 



c. leaves in various stages of growth ; 



d. roots. 



ii. Make a sketch of the clean-cut surface of a piece 

 of the rhizome, shewing 



a. external brown tissue consisting of the epidermis 

 and the subjacent hypodermal sclerenchyma ; 



b. the two lateral lines where a. is very thin, the 

 sclerenchyma being absent, and c. comes to the surface ; 



c. the soft parenchyma ; 



