No. 454-] OPHJOGLOSSACEJ- AXD MARSILIACE.^:. 



767 



there may be instanced Kaulfussia, whose venation is not very 

 different from that of Ophio^dossiim. and possibly a further 

 comparison mi^ht be made in the form of the leaf with the 

 palmately lobed leaf of Ophioglossum pahmUum. On the other 

 hand, the venation of Agiopteris or Dan^ea is almost identical 

 with that of Helminthostachys. (See Fig. 2.) 



Farmer (Farmer & Freeman, " The Structure and Affinities 

 of Helminthostaclns." Ann. Bot. 1899) has referred to the stip- 

 ules of the latter ,<;-enus and thinks they are not directly compa- 



rable to those of the Ophioglossacea , althou-h it is not quite 

 clear wherein the difference consists. 'I here cei tainl) .^eenis^to 

 be no essential difference between - 

 leaf base in Botrychium (Camplxdl 

 and those in Marattia or Danaa, alLh(m,i;h m the laltei" .i;eiieui 

 the stipules are more distinct. The; development ot >lii)ular 

 structures is especially marked in both ( )phu.-los>a< anc 

 Marattiace?e, while among the Leptospmangiata' the) aie^gtn- 

 erally absent except in the^^ Osmundacea;, uliich aic 



rangiate ferns. 



The markedly dorsiventral rhizome of Dana;a is strongly sug- 



