PTERIS. 169 



species is still more clearly exhibited when it attains its 

 greatest luxuriance, for the full-grown fronds then consist 

 merely of a series of pairs of branches from the bottom to 

 the top. The unrolled young fronds are very curious 

 objects, and the watching of their development will be 

 found full of interest. 



The stipes is downy while young, and furnished with 

 sharp angles, which, when mature, will wound the hand 

 severely, if it be incautiously pulled. The part under- 

 ground is black, like the creeping stem itself, and is 

 spindle-shaped just at the base, where it permanently 

 retains the downy or velvety surface w"hich was present in 

 the upper portions while young. Average specimens of 

 the fronds are tripinnate, that is, they produce a certain 

 number of pairs of branch-like pinnoe, which branches are 

 bipinnate. We must confine our further description to 

 one of these branches, selected from the lower part of the 

 frond, where they are more perfectly developed than in the 

 upper parts, — such a branch, in fact, as is represented in 

 Plate XVII. The general form is ovate, a little elon- 

 gated ; that of its pinna) (the secondary pinnae) narrow 

 lanceolate. These latter are placed rather closely together, 

 and are again divided into a series of pinnules, which are 



