EXPLANATION OF THE PLATES. 



PLATES XXXIII-XXXV. SPINULOSE FERN. Dryopteris spinulosa inter- 

 media, Plate XXXIII. 1-7. Young leaves and plants in early stages of 

 development. 1-3. Plants attached to prothalli. Plate XXXIV. i, 2. 

 Young leaves in later stages of development. Plate XXXV. i . Mature sterile 

 leaf. 2. Section of fertile pinna of mature leaf, X 2$. 



