AN ENUMERATION OP CULTIVATED FERNS. 



axis of the leaves at their base, globose, 1 -celled, traversed by 

 thread-like receptacles of two kinds : 1. (Antheridangia), 

 containing numerous small spores ; 2. (Oophoridangia), con- 

 taining large 4- sided spores. 



Genus 1 63. Plant, natural size. No. 1. 



1. I. lacustris, Linn. ; Willd. Sp. PL 5, p. 534 ; Bolt. Fil 

 t. 41 ; 8M. Crypt. 1. 173 ; Eng. Bot. 1084. Europe, 

 Britain. 



