POLYPODIUM. 151 



from six inches to a foot in height. The stipes, which is 

 fleshy and very brittle, is generally twice as long as the 

 leafy part of the frond ; near its base are a few small almost 

 colourless scales. The fronds are triangular, extended into 

 a long narrow point. In the lower part they are pinnate ; 

 but this distinction of the parts is seldom carried beyond 

 the two lowest pairs of branches, those of the upper por- 

 tions of the frond being connected at the base, in what 

 is technically called a pinnatifid manner : hence this Fern 

 is said to be subpinnate, which, in this case, means par- 

 tially pinnate, or pinnate at the very base only. The 

 pinnse have a narrow and acutely lance-shaped outline, and 

 are deeply pinnatifid; they usually stand opposite each 

 other in pairs, the lowest pair being directed downwards, 

 towards the root, and set on at a short distance from the 

 rest. The united base of the pairs of the other pinnse, 

 when they stand exactly opposite each other, exhibits a 

 cruciform figure more or less strikingly obvious ; and by 

 this mark, in conjunction with the subpinnate mode of divi- 

 sion, this species may be known from the other British Poly- 

 podies. The veins in the lobes of the pinnse are pinnate ; 

 that is to say, there is a slender midvein, from which al- 

 ternate venules mostly unbranched extend to the margin ; 



