FERNS; 



BlilTISH AND EXOTIC. 



ASPIDIE^. J. Smith, 



In many instances the only difference between Polypodiece 

 and Aspidiece is confined to the former having no indusium, 

 whilst the latter is furnished with an indusium; this, however, 

 is sometimes very small, and at others so soon detached from 

 the sori, that fronds must be examined, the one with a micro- 

 scope and the other at an early stage, in order that the difference 

 from Polypodiece may be detected. 



Mr. Smith remarks that there are above two hundred described 

 species of Aspidiece. 



Aspidiece is distinguished from Aspleniece mostly by having 

 circular instead of lateral sori, and when the sori is lateral it 

 is attached across the venule, instead of longitudinally in the 

 direction of the venules as in Aspleniece. 



Sori circular, with one or two exceptions, where oblong. It 

 is intramarginal, and has a special indusium, which is either 

 orbicular, produced from the centre, (central,) or reniform or 

 cucullate, produced from the interior side of the sporangiferous 

 receptacle, (lateral,) or occasionally attached all round the 

 YOL. YI. B 



