BRITISH FERNS. 87 



Smith, but I consider this to arise from the pressure of the 

 scales, for, in our British Ferns I have observed that when the 

 indusium is entirely absent, the thecse are not naturally attached 

 to either side of the vein, but to its back. In the pinna from 

 which I have made the drawing shewing the veins, this mass 

 near the rachis did not exist. 



I find that Mr. Smith was aware of the anastomosing veins of 

 Ceterach, a very obvious and distinguishing character ; but to 

 the best of my belief no author has alluded to it. I observe 

 that Presl places Ceterach in the genus Gymnogramma, in which 

 all the veins are free and unattached at their extremities indeed 

 he makes this a distinguishing character of the genus. I cannot 

 help thinking that the genera Gymnogramma and Grammitis 

 are separated on characters really too trivial to notice. 



Dioscorides (lib. iii. p. 234) greatly extols the medicinal 

 virtues of this humble fern ; he recommends a decoction of it to 

 be taken in wine during the space of forty days ; it is not quite 

 a universal panacea, but its powers seem very comprehen- 

 sive ; amongst other qualities he asserts that " calculos vesicce 

 comminuit" The same author alludes to its similarity to the 

 animal called Scolopendra, a comparison which almost every 

 author institutes, but the resemblance is not very manifest. 



The cut below represents a more usual form of Ceterach 

 officinarum than that at p. 85 ; the difference will be found in 

 the less complete separation of the pinnae. 



