28 BRITISH FERNS. 



Mr. T. B. Flower, after giving me Brecon as one of his 

 localities for P. calcareum, adds " The Brecon plant would 

 appear to be intermediate between P. calcareum and P. Dryo- 

 pteris ;" and I may observe that Mr. Flower appears well 

 acquainted with the plants known by these names. 



Mr. Francis, in his Analysis of the British Ferns, represents 

 both species as having the rachis bent at the union of the 

 branches, a character, according to Smith, possessed by Dryo- 

 pteris only ; he also represents the pinnulae of the second pinnae 

 in calcareum completely pinnate, which is far from being the 

 case in the original specimens: Mr. Francis also says, that 

 " its frond is rather large in size," while Smith speaks of it as 

 being smaller than Dryopteris. It is clear that the same plant 

 is not intended ; indeed, Mr. Francis's elegant figure represents 

 a plant I have not seen. 



Finally, Sadler, in his pamphlet, " De Filicibus Veris Hun- 

 gariae," a work displaying an intimate acquaintance with ferns, 

 observes of P. calcareum " This species is not yet sufficiently 

 established ; it differs from Dryopteris in its less size, the pinnulae 

 also being relatively less and almost entire, the masses of thecae 

 more or less confluent, and in having glandular hairs on the 

 rachis, and sometimes also on the fronds." 



The lateral veins are alternate, and either divided or simple, 

 according as the pinnula or lobe in which they are found is more 

 or less divided ; each terminates at the margin, bearing a circular 

 and perfectly naked mass of thecae near its extremity. 



The vignette below represents Eshing bridge, near Godalming, 

 in Surry. 



