HO HISTORY OF BRITISH PERILS. 



average height — the margins run nearly parallel almost to 

 the apex, where they narrow to a blunt point ; the stipes 

 rather exceeds a third of the length of the entire frond, 

 and is proportionally stout, maintaining this proportion 

 upwards through the leafy portion of the frond ; on its 

 lower part it bears a few scales, which arc blunt ovate, 

 membranous, and of a uniform light brown colour. The 

 pinna3 are elongate-triangular in their outline, the broadest 

 occurring at the base of the frond, the upper ones becom- 

 ing gradually naiTOwer, but all of the same general form, 

 namely, widest at the base, gradually tapering to the apex. 

 They are not divided quite down to their midrib, so 

 as to become, in technical terms, pinnate, but each 

 segment is attached by the entire Avidth of its base, and 

 connected by a narrow extension of its base with the seg- 

 ment next behind it ; all the segments having their apices 

 inclined rather towards the apex of the pinna. These lobes 

 of the pinna? are themselves oblong, with a rounded apex, 

 and a crenately-toothed margin. 



The midvein of the lobes talces a tortuous course, and 

 gives off lateral branches, which divide into several secon- 

 dary branches, one only of vrhich, that nearest the apex of 

 the lobe, bears a sorus. The fructification is confined to 



