THE ALPINE POLYPODY. 



never to occur in company with the more perfect sori, but only where the spore-cases are much fewer in 

 number than usual. To us they had the appearance of lacerated membranaceo-filamentous ex-ttnsions 

 of those points of the veins which formed the receptacles ; and they appeared to ariso from some abnormal 

 condition, which had limited the power of producing spore-cases to tho side or base of the receptacle, 

 while on the upper side the cells of the receptacle had been directly prolonged into tho indusioid 

 membrane ; but in no case have we seen what could be considered as a true indusium. On the other hand, 

 Mr. Rylands, of Warrington, who regards the plant as au Athyrium, has communicated the result of some 

 observations mado in 1855, in company with Mr. Wilson, from which tho following passages are quoted : 

 — "Iu those son which are large and fully ripe, the indusium could not bo seen, though I iinagino 

 dissection would show traces of it. One sorus was found still closed, tho si»rc-cascs little developed ; 

 it was reniform, and lay alongside the venule. In many of the smaller son remains of an indusium 

 was seen, and in two or three it was as nearly perfect as one may expect to find it The margin was 

 ladniated with fine projecting points. The laciuiatcd margins are produced by the rupture of tho 

 cuticle, and the fine points are tho cell-walls thereof. Tho indusium is very tender, shrivels, ami where 

 tho spore-cases arc numerous, is speedily concealed or perhaps displaced by them : it is smaller than in 

 the other forms of A thyrhm. These peculiarities seem to result from the rupture of tho cuticle taking 

 place early in tho progress of development of tho sori ; but that it has the true indusium of an Athyrium 

 I think cannot be further disputed." Subsequently, Mr. Rylands writes :— "The 'imlusia' of uljmlre 

 are not, I think, confined to the imperfect sori, though after bursting they soon shrivel and disappear 

 in tho larger ones. I have compared it with A. Filir-famina nolle, and though in texture, position, 

 and general character, there was little difference, I am compelled to admit that in tho caso of afjmlre 

 the spore-cases seemed to lie within the proper cuticle of the frond, while tho evidence of a distinct 

 membrane was much clearer in molle. This supports your view to some extent; but* all things 

 considered, is it sufficient to remove the plant from others so evidently its allies?" When so many of 

 tho sort— not only tho majority, but all, with few exceptions, and those exceptions having strongly 

 marked imperfect; or abnormal characters— really appear to be Die round naked masses of Potypodium, 

 wo have no alternative, repudiating aa wo do the other grounds of separation already adverted to, but 

 to retain this plant in that genus. 



'Hie Flexile Polyimdy— P. ALPB8TRE flexile— <Platk VII., d. e.) as communicated to us by Mr. 

 Backhouse, is certainly a very distinct variety, and may be a secies, the former being the view adopted 

 by its only discoverer, Mr. Backhouse, who writes :—" Dissimilar as it is from P. alpestre, I shall 

 continue doubtful of its specific difference if it docs not turn up in other places." It differs in being 

 more slender ami flaccid ; iu having a much narrower outline, and consequently shorter pinna;, with a 

 considerably reduced number of pinnules; in the form of the pinnules, which are oblong, narrowed below, 

 sessile or adnatc, and distantly toothed; in the very short stipes, becoming obsolete in the cultivated 

 plants ; and in a tendency to bear perfect sori at tho base of the frond, while the apex is barren— tho 

 reverse of what usually happens. The absence of stipes, which Mr. Newman includes in his definition 

 is not constant, the wild specimens sent by Mr. Backhouse having a distinct stij>es of about a couple of 

 inches ; this part, however, is always very short. The fronds are from six or seven to twelve or 

 eighteen inches in length ; the pinna*, spreading or more or less deflexed, short, with about six or eight 

 pairs of pinnules. Tho sori are few, six or eight on a pinnule, usually distinct In the cultivate! plant 

 the clusters are very numerous in tho lower half, and scarcely extend upwards beyond the middle of 

 the frond ; but this character is not constant, one frond communicated by Mr. Clapham, and the wild 

 fronds from Mr. Backhouse, being fructified throughout, and another obligingly forwarded by Mr. 

 Newman being fertile both at the base and apex. In this latter, which was only sparingly fructified, 

 tho spore-cases appeared for the most part to bo attached to the side of the vein, ami the sori were 

 slightly elongated rather than circular, indicating an affinity with Athyrium, and there was in some 

 cases a peculiar membranncco-filamentous development iu the position of an indusium, again indicating 







