On the British species of Polypodivm. 143 



cover a more decisive character, and supersede, with some 

 harsh comment, the genera proposed by the second, and in- 

 sist that the species must be divided thus, A — BCD ; in ano- 

 ther year a fourth author will laugh at his predecessors, and 

 insist that this, and this only, is a division on philosophical 

 principles, DA — BC. Let any one refer to our orchideous 

 plants, for a corroboration of these observations ; what is the 

 result? Every one knows the species; no one the genera. 



To return to ferns : — the shape and cover of the masses of 

 seed have always been considered valuable characters for ge- 

 neric distinction. But here a question arises, whether the 

 shape of the mass, or its situation, or the presence of a cover, 

 is the best and most available character : this will never be 

 decided. Even adopting the circular or linear form of the 

 seed, as a generic character, Linnaeus, Withering, Smith, Gal- 

 pine, and a host of other botanists, have associated, in the 

 genus Polypodium, Filix mas, having circular masses, with 

 Filix foemina, which has linear ones ; thus allowing the si- 

 milarity in general habit to supersede the distinction imposed 

 by themselves. Recent writers have, with as little hesitation, 

 taken Filix foemina from the genus Polypodium, and placed 

 it in the genus Asplenium. Now, if genera are of any value 

 at all, a whole tribe of closely-allied ferns, tender, fragile, de- 

 ciduous, alike in figure and fructification, might be associated 

 under a new generic name, of which genus Filix foemina, 

 the only species indigenous to Great Britain, might be 

 considered as the type. The genus might be named En- 

 phorium, on account of the exceeding abundance of its seed 

 when in a state of maturity and vigour. 



Leaving the beautiful Filix foemina to occupy its present 

 situation in the genus Asplenium, I will now offer a few re- 

 marks on those ferns which have the seed in nearly circular 

 masses, and to which Linnaeus gave the name Polypodium. 



1st. They appear to be of slow growth and very long life. 



2ndly. They are raised from seed ; and as they approach 

 maturity, they vary year by year, and often frond by frond, 

 both in general appearance, and in the cutting of the frond. 



3rdly. If a seedling be so situated as to lack sufficient 

 shade, moisture, or covering to its roots, all highly essential 

 to its arriving at perfection, then is its progress towards ma- 

 turity delayed, and the period of its seedling appearance in- 

 definitely prolonged. 



4thly. But so powerful is the command, 6 increase and mul- 

 tiply,' so innate throughout nature is the tendency to repro- 

 duce its kind, that those plants, in which the usual appear- 

 ances of maturity are thus delayed, do nevertheless produce 



Vol. II.— No. 15.,n. s. m 



