Ci BRITISH FERNS. 



size. Its fronds are from four or six inches to a foot in 

 length, bipinnate, lanceolate in form, supported on a brown- 

 ish-coloured stipes on which as 

 FIG. 18. well as on the rachis are scattered 



small bristle-like scales. The 

 more vigorous plants are nearly 

 erect, though sometimes some- 

 what spreading in growth. The 

 pinnae spread at nearly right 

 angles with the rachis, often op- 

 posite, and have an ovate-lan- 

 ceolate form. The pinnules are 

 of irregular form, often obovate, 

 or nearly so, sometimes un- 

 equally quadrate, but always 

 indented on the margin with 

 deep, sharp teeth, the larger 

 pinnules being first lobed, and 

 the lobes toothed, the smaller 

 ones simply toothed. The vena- 

 tion is tolerably distinct ; the 

 pinnules each having a tortuous 

 midvein, which produces forked 

 venules, and these produce vein- 

 lets, one of which extends to- 

 wards each serrature. The sori 

 are at first oblong, and covered 

 by an indusium of the same form, having a lacerated free 

 margin; but as they become old the sides become bulged out 

 so as to give them a roundish form, and the indusium 

 becomes obliterated. 



The variety microdon, a very rare plant, has pinnate fronds, 

 the pinnae being only undulated and lobed, not again pinnate. 

 This is rather a local species, being found only in the 

 southern and western parts of England, and in Wales, almost 

 always near the coast. It is found very luxuriant in the 

 Channel Islands. 



As might be expected, it evidently requires a mild and 

 sheltered climate, so that in a hothouse, where the tempera- 

 ture is not kept too high, or jn a green-house, it grows 

 freely; this cannot always be said of plants kept in a cold 

 frame, and never of plants fully exposed, unless the locality 

 is very favourable. 



Asplenium lanceolatum. 





