54 



BRITISH FERNS. 



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fronds are few in number, they rise early in spring, and disappear 

 K before winter. The figure of the frond is 



% linear, its position remarkably erect, and 



^ much more than a third of the rachis is 



naked: towards the base it has a few scat- 

 tered chaiFy scales. A remarkable character 

 of this species is the propensity of the frond 

 to decay and turn brown in spots ; this is 

 more particularly observable towards the apex 

 of the frond and pinnae. The fronds are 

 pinnate ; the pinnae, which are attached by 

 their stalks'only, are distant, very short, nearly 

 triangular, and pinnatifid, the pinnulae being 

 serrated. The fronds are fertile and barren, 

 the former are nearly twice the length of the 

 latter. 



The lateral veins in the pinnulae are many- 

 branched, and the anterior branch bears a 

 circular mass of thecae, about half-way be- 

 tween the midvein and margin. The masses 

 are covered by an indusium, which often re- 

 mains in situ after the seeds are fully ripe : it is 

 reniform or attached at a lateral point, which, 

 as the indusium shrivels, and the thecae swell, 

 is forced into the centre of them, and so 

 appears to be orbicular, and attached centrally, 

 as in the genus Polystichum. Sir J. E. 

 Smith does not seem to have been aware of 

 this structure, or of the importance of ob- 

 serving the characters of the indusium ; his 

 description of the indusium of cristata would 

 make it a Polystichum, while Lonchitis, " with 

 a notch on one side," would become aLastraea. 

 This carelessness is more particularly to be 

 regretted, because compilers unhesitatingly 

 copy, and thus perpetuate, these errors. 

 Mr. Beevis tells me that he found this rare fern near the 

 windmill, on Wimbledon Common : if this be the case, I am 

 inclined to think it must have been planted there. Many 

 botanists have industriously sought for it in this locality, but in 

 vain. 



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