EUPTEEIS AQUILINA. 



27 



very interesting ' Terra Lindisfarnensis,' to describe this species 

 as " gregarious." The young fronds make their appearance in 

 May : they are extremely susceptible of cold, and it is by no 

 means unusual to see the earlier fronds, before their expansion, 

 entirely destroyed by the late frosts in spring: I have observed 

 them cut down as late as the 20th of May. 



The fronds rise perpendicularly from the rhizome at une- 

 qual intervals : until they nearly reach the surface of the ground 

 the stipes only is discernable, the apex being rounded and dis- 

 playing no trace whatever of a foliaceous portion, (fig. 1) : a 

 slight and scarcely perceptible indentation does, however, exist 

 at the point a in that figure ; and the slight projection above 

 this, better shown at h, in the sectional view (fig. 2), contains 

 the future foliaceous portion. Figures 3 and 5 represent the 

 same frond in a state somewhat more advanced, and figs 4 and 

 6 are median longitudinal sectional views of the same. In all 

 these it will be seen that the foliaceous part is bent forward on 



l^^ 



the stipes, forming therewith a kind of hook ; a structure strik- 

 ingly different from that of Pteris tremula, represented at figs. 

 7, 8, 9, which, although generally held to be closely allied to 

 aquilina, very clearly exhibits the usual circinate vernation. It 

 may, however, be observed, that the extreme point of the bent 

 rachis has a slight tendency to exhibit a curve, as shown in 



