EXPLANATION OF THE PLATES. 

 Plates XLII-XLV. — Sensitive Fern. Onoclea 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 J. 4. Section of pinna of sterile leaf, X 2 J. Plate 

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



