68 CAMPTOSORUS RIIIZOPHVLLUS. WALKING-LEAF. 



more reticulated, or net-veined than the maturer and fruitful 

 ones (Fig. 2). Indeed it is our experience that when a frond is 

 abundandy fruitful, the veins are often wholly free. It may be 

 also remarked that in the enlarged drawing at p. 75 of Mr. 

 Williamson's " Ferns of Kentucky," the veins are all wholly 

 clear of each other. 



Asplcniuni pinnatifidiun is remarkable for it:i fertility. Often 

 early formed and small fronds are as completely covered with 

 sporangia as larger and more recent ones, and it has little dispo- 

 sition to make terminal buds ; while the Cainptosoriis is compara- 

 tively a sparse-fruidng fern, and makes up for this by its power 

 of increasing from terminal buds (whence comes its name 7^hizo- 

 phyllum). It would be curious if it should ultimately prove that 

 the one form has been evolved from the other by a sort of dif- 

 ference of opinion, as one might almost say, as to the best 

 methods of reproduction, and that the greater divarication of the 

 veins in the walking-leaf (which is really all the difference) is a 

 mere incident in the reproductive question. 



The Camptosorus under its older names has been long known 

 to botanists, having been noticed by Ray, Morison, Plukenet, 

 and others of the early English authors of the first part of the 

 eighteenth century. Gronovius had specimens sent to him 

 both by Clayton from Virginia and Golden from New York. 

 Michaux found it " not abundant" from " Ganada to Tennessee." 

 Dr. Gray says its home is from " west New England to Wiscon- 

 sin and southwards." The writer of this has found it abundandy 

 on the rocks running from east to west across the state in South- 

 ern Illinois, and Professor Lesquereux found it in Arkansas. 



Explanation of the Plate. — i. Complete plant. 2. Fertile frond. 3. Rooting point of 

 one frond. 4. Barren frond conspicuously netted-veined. 



