1891.] Morphology of Spore-producing Members. 273 



for example, the strobilus of Lycopodium, or of Equisetum ; it is not 

 difficult to see how, from a Bryophyte with an archesporium such as 

 that of Anthoceros, the strobilus might originate from the sporogonial 

 head, by partitioning off the archesporium (such as that seen in Ophio- 

 derma), and outgrowth of new members from the surface (such as are 

 seen in Helminthostachys) . The details of the process might doubtless 

 be different ; it is not even contended at present that this may have 

 been the mode of origin of all the stocks of Vascular Cryptogams. 

 But the point is that an elaboration similar to that which may be traced 

 in the spore-bearing members of the Lycopodince and Ophioglossacece of 

 the present day might, if carried out in a sporogonium such as that of 

 Anthoceros, result in a strobilus not unlike those of Equisetum or 

 Lycopodium. The gap between the Bryophytes and Vascular Crypto- 

 gams would thus be bridged over by a hypothesis based upon 

 analogy. I am fully aware how open such a hypothesis is to criti- 

 cism, but I think that it is better, after careful and widely extended 

 comparative observation, to put out the hypothesis than to be content 

 with no clear hypothesis at all. More especially is this so in the 

 present case, where no intermediate types are at present known to 

 exist, and where we have no special reason to expect that such types 

 will be discovered. 



The above description makes it evident that a revision of termino- 

 logy of spore-bearing members will be necessary ; if the spore-bear- 

 ing member of the Ophioglossacea3 be homologous with the sporan- 

 gium of Lycopodium, it is obviously undesirable to call it a " fertile 

 frond." It could not, however, be termed a sporangium without 

 violence to the meaning of this word. I have not yet arrived at a 

 conclusion on such points as these, and shall defer the definition of 

 the terms to be used until the memoir, of the contents of which this 

 is a short and partial preliminary statement, shall be ready for pre- 

 sentation to the Society. 



In conclusion, no reference has been made in this statement to the 

 higher plants. Clearly the enunciation of new views with regard to 

 the lower vascular plants must affect opinions as to the morphology of 

 the higher. The interpretation of these will ultimately have to 

 depend upon conclusions drawn from the study of the lower types. 

 Hitherto it has been the practice to read the morphology of the lower 

 forms in terms of the morphology of the higher ; the converse will 

 have to be ultimately adopted. Nevertheless, I have abstained at 

 present from touching upon such questions as these, partly because 

 such discussions would obscure the present issues, partly because the 

 time has hardly yet come for any general statement. 



The Society adjourned over the Christmas Recess to Thursday, 

 T anuary 14, 1892. 



