FERNS I BRITISH AND FOREIGN. 



162. PILULABIA, Linn. 



Plants with filiform leaves, from a creeping rhizome under 

 water. Sporangia (conceptacles) radical (at the base of the leaves 

 on the rhizome), globose, coriaceous, 2-4-celled, 2-4-valved, each 



Genus 162. Plant, natural size. No. 1. 



cell containing different kinds of bodies : 1. (Antheridangia), 

 consisting of vesicles containing many minute granular spores ; 

 2. (Oophoridangia), each containing a single large spore. 



1. P. globulifera, Linn. ; Willd. Sp. PL 5, p. 535 ; Bolt. 

 Fil. t. 40 ; ScJik. Crypt, t. 173 ; E-ng. Sot. t. 521. 

 Europe and Britain. 



163. ISOETES, Linn.'. 



Plants with awl-shaped leaves, from a thick creeping rhizome 

 under water or out of water. Sporangia (conceptacles) borne in the 



