52 



BRITISH FERNS. 



The lateral veins are forked about half way between the 

 midvein and margin ; after the fork the anterior branch bears a 

 nearly circular mass of thecae, which are covered by a smooth, 



lead-coloured indusium, reniform, or 

 attached to the vein at the point 

 where the stalks of the thecae are 

 inserted ; the indusium is more perfect, 

 conspicuous, and lasting than in any 

 other British fern ; the veins do not 

 quite reach the margin of the pinnulae, 

 and the anterior is not quite so long as 

 the posterior. 



Although this fern is of very constant 

 figure, yet it occasionally departs a good 

 deal from the typical form; a frond 

 preserved in the herbarium of Mr. 

 Winch, now in the possession of the 

 Linnean Society, is simply pinnate, the 

 margins of the pinnae being waved, but 

 not divided. This variety is precisely 

 analogous to the lonchitiform variety of 

 Polystichum aculeatum ; it is not a 

 seedling, or young plant, being itself in 

 full fructification, as shewn in the 

 accompanying figure. Three other 

 varieties are named by Mr. Francis, 

 viz., 1. Variegatum. White-tipped, 

 and edged with green. 2. Recurvum. 

 Pinnae crisped, turned down; frond 

 small, rachis smooth. 3. Spinosum. 

 Pinnules serrate, smaller blended to- 

 gether, larger auricled. 

 Much has been said of the value of the rhizoma of Filix-mas 

 as a vermifuge, and formerly it was employed in this capacity 

 somewhat extensively: the result of my inquiries on the subject 

 is, that it has long ceased to be an article of any commercial 

 importance. 



