22 



the serratures terminating sharply. The lateral veins of the lobes 

 divide into several branches, the uppermost of which bear the sori, 

 which thus form a line on each side the midvein about half-way 

 between it and the margin, extending to the extremity of each lobe 

 or pinnule. The indusium is nearly circular, very permanent, and 

 conspicuous from the contrast of its white or pale leaden hue with 

 the black or dark-coloured thecae. The regular arrangement of the 

 sori is frequently disturbed in luxuriant specimens by super-develop- 

 ment, and they generally become confluent in maturity, a state 

 attained in the latter end of August. The fronds remain green in 

 mild seasons throughout the winter. 



This is not at all a shy species under cultivation : it succeeds best 

 in turfy peat, without admixture of any other soil, and, though 

 naturally an inhabitant of boggy ground, seems to bear drought 

 better than some of those belonging to drier situations ; neither is 

 shade so essential as to render exposure to the sun a matter of any 

 importance : indeed I have this summer a specimen, two feet high, 

 and in fine condition, growing on a sloping bank, and quite unshaded 

 from sunrise to three o'clock in the afternoon. 



The specific name, cristata, has been cavilled at by some botanists, 

 but was evidently bestowed on it by Linnaeus, in consequence of a 

 fanciful comparison between the cluster of its peculiarly erect fronds 

 and the aigrette of vertical feathers on the head of the peacock, Pavo 

 cristatus: that of Ehrhart, Callipteris, literally beautiful fern, adopted 

 by DeCandolle, associates ill with a species not at all remarkable 

 among its congeners for the attribute expressed. 



LASTREA RIGIDA. Rigid Lastrea. TAB. XI. 



Fronds triangular-lanceolate, bipinnate, glandular : pinnules ob- 

 long, obtuse, lobed, the segments broad, rounded, 2-5-toothed. 

 Indusium persistent, fringed with glands. 



Lastrea rigida, Presl Aspidium rigidum, Swartz. Smith. Hooker 

 E.B. Lophodium rigidum, Newman, Hist. Brit. Ferns, 175 

 Polypodium fragrans? Linnaus. 



This appears to be a very local species, having hitherto been 

 almost exclusively found in the mountainous districts of the north 

 of England. It was first noticed as a British fern by the Rev. Mr. 

 Bree, who met with it growing on Ingleborough, and subsequent 

 researches have shown that it is abundantly distributed along the 

 limestone formation of Yorkshire, Westmoreland, and Lancashire. 

 Mr. Finder and others have remarked upon the profusion in which 

 it grows, at intervals, between Arnside Knot (near Silverdale, West- 

 moreland) and Ingleborough, springing from the deep fissures of 



