ATHYRIUM. 89 



ends, appearing more curved than before, and the sorns 

 thus becomes finally roundish in outline, and the indusinm 

 apparently almost circular with a lateral notch; in this 

 state it somewhat resembles a Lastrea. On one side the in- 

 dusium is fixed longitudinally to the side of the vein which 

 forms the receptacle ; its other margin, the anterior one, or 

 that towards the midvein of the pinnule, becomes free, and 

 is then seen to be fringed, or split into a number of hair -like 

 segments. This description applies to the commoner forms 

 of the Lady Pern, which, however, are very variable in size, 

 according to the situation and circumstances which influence 

 their development, sometimes scarcely exceeding a foot in 

 height, and at other times reaching the height of four or 

 five feet, the latter being the result of growth in a damp, 

 shady situation, the former the consequence of a more exposed 

 and drier locality. 



Of the varieties we shall notice only the most striking, 

 and of these convexum is botanically the most distinct, and 

 probably should be regarded as a distinct species. It differs 

 from the commoner Lady Perns in its more lady-like pro- 

 portions, both its fronds, its pinnse, and its pinnules being 

 smaller and more slender than in them. The fronds seldom 

 exceed two feet in height, and are often less ; they are more 



