EXPLANATION OF THE PLATES. 



ISO ETES. Plant of I. lacustris (1); sporocarp containing minnte spores, cut acr IBS (2) 

 enlarged; same divided lengthwise (5); sporocarp with coarse spores, divided 

 lengthwise (8j ; and (4) three coarse spores more magnified. 



AZOLLA. Plant (1): a portion magnified (2), with two kinds of organs; s'erile sporocarp, 

 or antheridium, more magnified (3) ; fertile sporocarp more magnified (4); the same 

 burst open, showing the stalked sporangia (5) ; one of the latter more magnified 

 ($); another bursting (7) ; and three spores (8), beset with bristles. 



THE KYT>. 



