EUPTERIS AQUILINA. 



29 



general appearance. When this inerassated portion of the sti- 

 pes is cut through, either in a direct or oblique direction, the 

 section bears a regular figure, as repre- 

 sented in the annexed cut, the left-hand 

 section being direct, the right-hand one 

 oblique. This figure is by many said to represent an oak tree, 

 and is called King Charles in the oak ; by others it is supposed to 

 resemble a spread eagle, hence the specific name of " aquilina " 

 given by Linneus. From Mr. Francis's ' Analysis of Britsh 

 Ferns ' (p. 55), we learn that this appearance " was a matter of 

 notoriety at a very early period. Thus we find," says that au- 

 thor, " in a most rare little book, entitled ' A Dyaloge or Com- 

 munycation of two persons devysed or set forth, in the Latin 

 Tonge, by the noble and famous clarke Desiderius Erasmus, 

 intituled. The Pilgrimage of pure Devotion newly translatyd 

 into Englyshe' (no date, supposed to be 1551), is the following 

 curious passage: — 'Peraventure they ymagyne the symylytude 

 of a tode to be there ; evyn as we suppose when we cutte the 

 fearne stalke there to be an egle. ' " Dr. Johnston, in his 

 ' Terra Lindisfarnensis,' says the mark is also compared to the 

 " impression of the deil's foot ; " an impression, by the way, 

 with which I am not so familiar as to be able to decide on the 

 aptness of the comparison. 



The frond is killed by the first frosts of autumn, however 

 slight they may be : it instantly turns to a deep brown colour, 

 but remains perfectly undecayed, and frequently in an erect 

 position, during the whole winter. 



When fertile, the lobes are incurved or con- 

 volute at their edges, and their elasticity is so 

 invincible, that it is very difficult to maintain 

 the lobe in a flat position, adapted for an exa- 

 mination of its fructification. The lateral veins, 

 which are placed either opposite or alternately, 

 are twice dichotomously divided before reach- 

 ing the margin, where they are united together 

 by means of a marginal vein. The accompa- 

 nying diagram shows the formula of venation 

 in a lobe which has been flattened for the pur- 

 pose of exhibiting it more clearly. Attached 

 to the marginal vein, a a, and extending throughout its length. 



