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^. 



