THE AMERICAN NATURALIST. [Vol. XXXVIII. 



extremely probable ; but that the lowest members of the series 

 are to be connected with forms in any way like the Lycopodiaceae 

 appears to the writer exceedingly doubtful. The direct origin 

 of a type like Ophioglossum from an Anthoceros-like prototype 

 has been considered at length elsewhere (Campbell, — loc.cit., 

 p. 515) and will not be discussed further here.^ 



The numerous structural resemblances in both gametophyte 

 and sporophyte between the Ophioglossaceae and Marattiaceae 

 are too great to be passed over, and indicate a genuine relation- 

 ship between the two. It seems to the writer that the impor- 

 tance of those nln ious resemblances has been rather minimized 

 by some recent authors, and it may be just as well to call atten- 

 tion afresh to some of the m(«t striking ones. 



Our knowledge of the gametophyte of the Ophioglossaceae is 

 now pretty complete, owing to the important researches of Jef- 

 frey (The Gametophyte of Botrychium virginianum, Proc. Canad. 

 hist. V, 1898) and Lang (On the prothaUi of Ophioglossum pen- 

 dulum and Helminthostachys zeylanica, Ann. Bot. 16, 1902). 

 The tormer lias described in detail the prothallium of Botry- 

 c/n/iiii viro-iniannin, while Lang was fortunate enough to pro- 

 cure fairly complete material of Opliioglossnin pendulum and 

 Hclminthostachys rscylamca. so that all three genera are repre- 

 sented. ,'\s might be expected, there is a g0(xl deal of similar- 

 ity, this being most marked between Botrychium and Helmin- 

 thostachys. All agree in having a subterranean prothallium 

 which is destitute of chlorophyll, thus resembling the prothallia 

 of certain species of Lycopodium. It is highly improbable that 

 this condition is a primitive one, however, and too much stress 

 cannot be laid upon it in making a comparison with the green 

 prothallia of the Marattiaceae, with which otherwise there is a 

 close agreement, especially in the case of Ophioglossum. As 

 some species ot L\-co|)odium have a green prothallium, and chlo- 

 rophyll has been tound under certain circumstances in the pro- 



