THE COMMON POLYPODY. 



This Forn is cosily cultivated, if light porous soil is used, anil the rhizoincs arc kept on the surface of 

 Hie soil. When unnaturally planted deeply, or in stiff retentive soil, it dwindles and often eventually 

 perishes, Mr. Newman, ap]>arcntly founding his opinion on the circumstance of its being frequently 

 met with growing on pollard trees, considers it to bo of parasitical habit This circumstance would, 

 however, give it only an epiphytal not a parasitic character; but as it is frequently found, fully as 

 rigorous, growing among porous earth and on sandstone, these aro all probably mere accidental 

 conditions, the essential ones being constant moisture more or less in quantity, perfect drainage, and 

 moderate shade. It even exists in health naturally with little or none of some of these conditions about 

 it, as many an old wall bears evidence. It increases readily by dividing the branching rhizome. 



There are in this species many deviations from the typical form which has been already described ; 

 but they are rather of importance to the horticultural enthusiast than to the botanist : except in so far 

 as the latter may rogard them as evidences of tho manner in which, and the extent to which, common 

 species arc known to vary ; and may hence learn to appreciate rightly tho less familiar differences which 

 are found to exist amongst exotic species. It is, however, chiefly for the information of the now 

 numerous class of Fern cultivators, most of whom tekc an interest in these variations, that they will 

 be enumerated hereinafter under distinguishing appellations. 



That form of the Common Polypody which differ* in the least degree, albeit constantly, from tho 

 normal state, has tho ends of its lobes gradually tapering off to a narrow point* instead of being nearly 

 equal in width to the end, and there more or less blunt A somewhat more diverse form has the points 

 of the lobes acute as in the last, but their margins are at the same time deeplv notched, the notches 

 forming a series of coarse double serraturcs. This state has sometimes a tendency to bifurcation at the 

 tips of the lobes, and what is mom remarkable, the sori aro not unusually decidedly oblong, in which 

 respect it deviates from tho generic type- Another slightly varying form has the ends of some or all of 

 the lobes divided, with tho divisions divaricate, so that the lobes become more or less manifestly two- 

 forked. Occasionally more than two [joints are developed to each lobe, and we have thus an indication 

 of the nature of the taeselled apices which aro common in some other species of Ferns, 



Sometimes the fronds acquire breadth rather than length, assuming a broad oblong or ovate-oblong 

 outline ; aud this is occasionally accompanied by various degrees of marginal division in the primary 

 lobes, showing a transition towards the more highly developed bipinnatiiid varieties* wmihtccrum ami 

 cambrienm. The most simple condition of this abbreviated and widened form, in which the apices are 

 usually acute aud the margins finely serrated, aud which is almost or quite identical with the Xorth 

 American plant called P. virginianum, and nearly so with the Madeira, plant called /\ canariense in 

 gardens, is apparently not common in this country, but has been communicated from near Hereford by 

 Dr. Allchin. It is when deeply crenato-lobate, that this type of variation approaches the more highly 

 developed or compound forms above alluded to ; this, too, sometimes varies with oblong sori. 



The Irish Poly]M>dy — 1*. vui/saiek skmu.aceiium — (sec Plate II,), of which typo there appears to bo 

 some slight variations, and which, moreover, is not confined to Ireland — has the fronds irregularly bipin* 

 natifid, in this respect approaching the Welsh Polypody; but the latter is more regularly and univer- 

 sally bipinnatifid, and is, likewise, always barren, whilst the former is more or less fertile. The fronds 

 are from a foot to a foot and a half long, elongate-ovate, piimatilid, in the lower part almost pinnate. 

 The primary lobes arc narrow and deeply serrate at tho base and apex, deeply ptnnatitid about tho 

 middle ; the secondary lobes or lobules are linear, acute or bluutish, serrate, longest at the lower part of 

 th© frond, becoming shorter upwards. Along these lobules tho veins from tho principal midvcin 

 extend and become branched, the branches dividing into from two to three venules ; in the other parts, 

 the veins arc arranged similarly to those in luxuriant examples of the normal form. The upper half 

 of the frond is fertile, and in this fcrtilo portion the lobes aro scarcely subdivided, the uppermost ones 

 being merely serrate or crcimto-scrrate ; the development of tho lobules, and of the sori, aro consc- 





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