No. 503] 



NOTES AND LITERATURE 



739 



modification of cither a foliar or caiilinc organ. The question is 

 left open whether the sporangiophore is to he regarded as the 

 elaboration of a single sporangium, like that of Lycopodium, but 

 it seems to us that the origin of the sporangiophore as a com- 

 pound structure from the beginning, is more in harmony with the 

 facts of comparative anatomy. 



The acceptance of this view will we believe help to solve some 

 of the most puzzling questions as to the affinity of the primary 

 pteridophytie stocks. While convinced of the real affinity be- 

 tween the Ophioglossacea* and the true ferns, we have also more 

 than once called attention to the marked resemblance between 

 the gan.etophyle of Kquisetmn and that of the lower ferns ;^and 



that are probably not without significance. If then we admit 



division of the Pteridophytes, it is quite conceivable that from 

 some common ancestral form having a large green gamctophyte 

 like that of the lower ferns, two types of sporangiophoric sporo- 

 phytes may have arisen, one developing the strobiloid group of 

 sporangiophores, as in Equisetum, the other a single large 

 sporangiophore like that of Ophioglossum. There is very good 

 reason to suppose that the sporangiophore of the Ophioglossacea* 

 is not an appendage of the so-called sporophyll. hut is a quite 

 independent organ, the sterile lamina being rather an appendage 

 of the sporangiophore than the reverse. 



In spite of Professor Power's argumenl we car. not but feel 

 that the resemblances between the OphioglossaceaB and the true 

 ferns are too numerous and exact to be explained on any other 

 ground than that of a real affinity: but this does not lessen 

 the importance of his explanation of their probable affinity with 

 the Equisetales and Sphenophyllales. 



The classification of the Filicales excluding < )phiogloss;ire;c 

 is that already elaborated in his memoirs on spore-producing 

 members. Three -roups of the Filicales are recognized. One. 



