ADIANTUM FED A 7 I '.]/. 1 1 1 



becomes straight again (or almost so), and very 

 gradually resumes the same position as before the 

 rupture of the sporangium. 



E. THE PROTHALLIUM. Examine prothallia of 

 various ages. Notice 



1. The shape and size. 



2. The cellular structure, best seen in a mounted speci- 

 men. 



3. The cluster of rhizoids on the under side. 



4. That in a prothallium with a young fern plant attached 

 the plant arises from the under surface. 



5. Draw. 

 MINUTE ANATOMY. 



A. THE STEM. Cut a transverse section and examine 

 with a low power. Make out the following parts : 



1. The single outer row of cells, the epidermis. 



2. A considerable thickness of brown 1 thick-walled tissue, 

 the peripheral sclerenchyma. 



3. A circular, oval or Q -shaped mass of whitish tissue, 

 most of which is \fatfibro-vascnlar bundle. 



4. Surrounding this bundle, and marking its outline, a 

 chain-like row of minute oval cells, the bundle-sheath. 



5. Entirely or partially surrounded by the fibro-vascular 

 bundle, a mass of axial sclerenchyma similar to the peri- 

 pheral. 



Examine the section with a high power and study in 



Yellowish in very thin sections. 



