EXPLANATION OF THE PLATES. 



PLATES XLII-XLV. SENSITIVE FERN. Onodea sensibilis. Plate XLII. 

 i. Young plant attached to prothallus. 2-6. Young leaves in early stages 

 of development. Plate XLIII. Young leaf in later stage of development. 

 Plate XLIV. i. Mature fertile leaf. 2. Mature sterile leaf. 3. Section of 

 pinna of fertile leaf, X 2^. 4. Section of pinna of sterile leaf, X 2$. Plate 

 XLV. Leaves intermediate between the mature sterile and fertile leaves. 



