ATHYRIUM PILIX-FEMINA. 309 



margin : the attachment of the clusters describes a concave, 

 rather than a direct line, as in Asplenium, and may be called 

 crescentic. From Hemestheum, Lastrea, Lophodium and Dry- 

 opteris, it differs in having the clusters of capsules liuear rather 

 than circular, attached to the side rather than to the back of the 

 vein, and the involucre which covers them attached longitu- 

 dinally rather than transversely. Whether it be distinct from 

 Pseudathyrium is a graver and more difficult question : my own 

 inclination is to unite them, but supposing this the philosophi- 

 cal solution of the question, how are we to manage the generic 

 name ? The species of Pseudathyrium are emphatically ex- 

 cluded from Eoth's genus Athyrium, by that learned author's 

 definition of the involucre ; and the species of Athyrium can- 

 not be comprised in the genus Pseudathyrium, because that is 

 distinguished by the absence of all involucre. Again, the two 

 genera will not blend in one, because Eoth's type-species of 

 Athyrium is Asplenium fontanum, and his second species 

 Asplenium Halleri. Anticipating the time when characters 

 founded on the absence, presence, size, or form of an involucre 

 among Filicacete, will be regarded as of no higher importance 

 than those founded on the absence, presence, size or form of 

 a petal among Eanunculacese, I cannot but also anticipate the 

 eventual union of plants so similar in habit as Filix-femina 

 and alpestre, in a genus to which a new name may perhaps 

 be given. The difficulty, in such an arrangement, lies in 

 releasing the botanical mind from the cramping trammels 

 which it has so long regarded as necessary. It is imjpossible 

 for botanists to neglect the involucre ; its characters are not 

 only patent and manifest, but, what is a matter of stiU greater 

 importance, are susceptible of perspicuous definition. Still, if 

 the botanist seek to found on its variations higher groups than 

 little clusters of species, which, like those known under the 

 names of Ilvense, fragile, aculeatum, dilatatum, Filix-mas, or 

 Filix-femina, may or may not be divided into species at the 

 option or caprice of each successive author, he will find him- 

 self inextricably involved in the most tangled and unnatural 

 combinations. 



With regard to the genus Athyrium, as composed by Eoth 

 of two groups, I am clearly of opinion that it cannot stand ; 

 the fontanum group and the Filix-femina group will not 



