584 



FILICES. 



a few times, and is no argument against its general character, 

 because it is obvious that in a spherical or capitate cell, open- 

 ings may escape notice when viewed by a microscope of small 

 penetration. 



In Ceterach another circumstance occurs, on which I am 

 disposed to attach considerable weight ; which is, that how- 

 ever evidently the ramenta formed on the axis, and between it 

 and the fronds, resemble those which I suppose to be the 

 fertilising organs, yet those formed subsequently to the ca- 

 pitate ones, are formed so much on a different plan that no 

 terminal cells whatever are formed. The distinction alluded 

 to, will at once, be evident by comparing a ramentum of the 

 stipes, with the vast majority of scales on the frond, and it is 

 equally obvious on very young fronds in which the peculiar 

 ramenta are attached beneath the lower half. 



On a single lobe of a very young frond both in Cryptogram- 

 ma and Ceterach, all stages of these bodies are to be traced 

 with sufficient exactness : those at the base appearing 

 just to have discharged their functions, those toward the 

 centre present the appearance of perfection ; those beyond, 

 every stage from the first appearance of the terminal leaf cell 

 to its pedicellation, decided capitation, and engorgement with 

 grumous granular matter. 



It then became a question to ascertain whether any pecu- 

 liarities were to be found among these organs in barren fronds, 

 but none have been detected by me. 



From examination of the youngest plants of Adiantum I 

 could meet with, I believe that the ramenta make their ap- 

 pearance with the 3rd or 4th frond ; near the base of the first 

 circulate one of these young plants, they are in some plentiful. 



The rarity of barren fronds may be in some measure attri- 

 butable to the abundance of male organs, at any rate no proof 

 is to be deduced from their casual occurrence. It then became 

 a matter of interest to examine, when the ramenta make their 

 first appearance. 



The means I possess are far too humble, to enable me to 



