236 



Methods in Plant Histology 



the. plants are often in the spray of cataracts and the lower part of 

 the trunk is often washed by mountain streams, a thousand tips 

 might be secured from a single specimen. 



The roots of Angiopteris, which become as large as a lead pencil, 

 may be secured in some greenhouses. They cut easily after fixing 



FIG. 78. Osmunda cinnamomea: photomicrograph of sporangia with spore mother 

 cells in various stages of division; fixed in Flemming's weaker solution and stained in 

 iron-alum haematoxylin ; from a preparation by Dr. S. Yamanouchi. X114. 



in formalin alcohol and furnish a fine example of the exarch protostele, 

 common to all roots. 



The structure of the leaf will appear in sections cut to show the 

 sporangia. 



The Sporangia.- -To illustrate the character of the annulus, 

 select sporangia which are just beginning to turn brown. Fix in 

 formalin alcohol and dehydrate as if for paraffin sections; after the 

 absolute alcohol, transfer to 10 per cent Venetian turpentine. Stain- 

 ing is neither necessary nor desirable. 



