THE BRITTLE JILADDEll FERN. 



smooth, oblongdanceolate, rab-blpinnato, faipinnatu, or rarely tripinnate. Pimm ovate-lanceolate or 

 oblong-lanceolate, with the pinnules usually distinct, but sometimes more or less decurrent or connected 

 by a wing to the rachis. Pinnules of the more typical forms ovate at the base of the pinna?, oblong 

 towards the apex, generally acute but sometimes bluntish; the larger deeply pinnatifid, with oblong 

 toothed lobes ; the smaller inciso-dentate or more shallowly toothed, the teeth generally acute. In the 

 «w#wtota series of forms the pinnules arc narrower, and more conspicuously and acute) v toothed; in 

 the deniata series, they are not so much separated, and are blunter, and usually, though not always, 

 less deeply toothed, but always with the teeth blunt 



Venation of the larger pinnules consisting of a flexuous midvein, from which a branch or vein 

 proceeds along each lobe, giving off secondary branches, or vetntte*, mostly simple, one of which 

 proceeds to the tip of each marginal tooth. The smaller pinnules more or less resemble the larger of 

 these lobes, and are also similar as regards their venation. 



Fructification scattered over the whole back of the frond. Sort roundish in outline, numerous, 

 borne on nearly all the branches of the veins in fully fructified fronds, and thus in the more divided 

 forms appearing to bo scattered without order over the whole surface, but in the less divided forms 

 more evidently placed in a line, near the margin of the pinnules, as they often are in the lobes of the 

 larger ones, though hi some forms they arc situated nearer the midrib than the margin, and often in 

 age become confluent; indusiate, medial on the veins- Indusium a thin smooth delicate hooded 

 membrane, attached behind the sorus, a little to one .side, cither truncate and thus roundish, or pro- 

 longed at the point and thus acutely or acuminately ovate ; at first iuflected forwards over the spore- 

 cases, soon, however, becoming reflected backwards and shrivelled ; the anterior margin either entire, 

 or split into narrow segments. Spore-oases roundish obovntc. Spores round or oblong, strongly cchinate. 



Duration. The caudex is perennial The fronds arc annual, appearing in April or May ; tliey 

 quickly arrive at maturity, and are followodby others in succession through the summer; and 

 arc destroyed by the early frosts of autumn. 



is 



Viewed as a collective species— and it cannot be satisfactorily viewed in any other light— this Fern i 

 easily enough recognised by its small slender fragile bipinnatc oblong-lanceolate fronds, and the peculiar 

 hooded or semicalyciform indusium. which in the early stages of the fructification may bo seen enclosing 

 the roundish masses of spore-cases. It is a plant so polymorphous in character that the S|>ecies which 

 botanists have from time to time endeavoured to separate from it, though sometimes assuming a 

 distinct-looking aspect> arc at other times not easily to be recognised, and are scarcely to bo defined 

 permanently, even as varieties. The Oystopteris fragilh may indeed be considered as being, like the 

 Athjftturn FUix-fwrnina and Lastrea ttitatatu, a botanical ignis fatutts, alluring the incautious novelty- 

 seeker among the quagmires of species-making, in which, when at length his mental vision becomes 

 cleared by more extended observations, he finds himself hopelessly floundering. 



The indusium of Cyst&jHeris when assuming the truncated semicalyciform character it sometimes 

 bears, stands in the same relation to the hemitelioid scales found behind the sori in some species of 

 AUophUa, as the more perfect cup in Woodwt— a true cup in some exotic species— does to that of 

 Cyttthea. These genera thus become connecting links between the polypodiaccous and cyatheaceous 

 series. Cystopteris has also a close aflinity with that genus of davallioid ferns, called Awophorm, 



This is a pretty littlo fern for the cultivator, affording some variety in his collection, and thriving 

 well either in ]>ots in frames or greenhouses, or on open shady rock-work in localities which enjoy a 

 moderately pure atmosphere. The soil may be composed of light turfy peat and loam, with sand, in 

 equal parts, ami the drainage should be ample. It increases readily by division or from the spores. 

 The fronds are frequently damaged by the ravages of a yellow fungus (Uredo jUicum), which 

 Spreads rapidly, and soon spoils those plants which are seriously attacked From its most commonly 

 occurring on plants grown in houses, we had thought the appearance of the fungus to be owing to the 



