GENERAL REMARKS. 



583 



ramenta at the points of elongation of the axis, there is still 

 however a peculiarity in those connected with the fronds. 



I believe that in some instances, these bodies assume after 

 their functions have been performed, the size of ordinary 

 ramenta. The external characters of the ordinary form of 

 ramenta are too well known to require any remarks, those to 

 which I would beg to direct attention are obvious modifica- 

 tions, the only difference perhaps being in the greater 

 size of the terminal cell. In Adiantum, those I have describ- 

 ed represent rather closely the ramenta of the axis in their 

 earlier stages, they however present sufficient peculiarities to 

 entitle us to consider them as organs possessing different 

 functions. 



I have before alluded to a certain disposition visible in these 

 organs, this I have traced in 3 out of 4 of the instances, par- 

 ticularly in Ceterach and Cryptogramma, in which it consists 

 in an inflexion of these bodies, so that their heads or terminal 

 cells are brought into juxta position with the surface of the 

 young frond, and as it would appear towards its margin. 



In Adiantum (the only species of the 4 with glabrous 

 fronds,) they appear to be so directed as to be placed in com- 

 munication with the centre of the axis of gyration. 



But of these obscure appearances, the most evident are 

 those which occur in these bodies afterwards, and which, from 

 analogies fresh in my memory, I incline to believe indicate 

 that they have performed their functions. 



I allude not so much to the colouring of brown, because 

 this appears universal among ramenta, which can have had 

 nothing to do with the important functions of fertilisation, 

 but to a certain appearance of aggregation of grumous mat- 

 ter, in, but especially about the septa of the cells, especi- 

 ally conspicuous in Ceterach and Cryptogramma, in both 

 which the terminal cells have been seen apparently open : 

 and in one or two instances these openings have appeared in 

 connection with an eruption of the very minutely granular 

 grumous matter. This appearance has been met with only 



