EXPLANATION OF THE PLATES. 
Pirates XXXITI-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.—1, 2. 
Young leaves in later stages of development. Plate XXXV.—1. Mature sterile 
leaf. 2. Section of fertile pinna of mature leaf, x 24. 
