446 



REPRODUCTIVE ORGANS 



these last have a single terminal cell, which in fact must be the same 

 in every really cellular growth sooner or later, the last degree of 

 formative power being the production of a single cell. 



At a subsequent period, still an early one, the terminal cell is 

 fuscous-brown, and this colour then extends to the next in various 

 degrees, but if it reaches the basilar ones at all, it does so at late 

 periods. The base of the terminal cell, and parts of the parietes of the 

 next and next, present a coagulated appearance, precisely as in cer- 

 tain mosses. 



No such thing as a petiolate leaf occurs in acrogens, all are at- 

 tached by a broad base ? Of acrogenous leaves, those only are leaves 

 whose attachment is at right angles with the stem; the rest are 

 divisions of a frond. Thus far with the ramenta. The divisions of 

 the frond, are, I find, not gyrate, but rather cochleariform involate. 

 The future reproductiveness is settled at a very early period, and 

 is distinguishable under the microscope by a sort of margination of 

 the frondlets. In the earliest stage I have looked at, the margin is 

 greenish, striated by narrow cells, and passes into the body of the leaf 

 gradually ; the greater development is perhaps central ; even now 

 the bulk of the cells of the leaflet have green granules, and are opaque 

 from air. The vessels are marked out, or at least their future course, 

 and along them the opacity from air does not exist, so that the veins 

 appear depressed. 



The next stage presented a greater development of an isolation 

 of the margin, but no other change. The next presented an isolation 

 of the margin, which remains almost white, the other part being 

 green, but more so because of a thickening as it were along the base 

 of the marginal part, and an evident deposit of grumous matter, from 

 which, under every circumstance new tissue seems always to be de- 

 veloped. Pressure causes its discharge, its contents were unappre- 

 ciated by my poor instruments ; after this the leaflets revert to the 

 appearance of the second stage. Here I ceased for the day, having 

 I think ascertained that ferns are endorhizal, and that the pri- 

 mary divisions of the roots hence have sheaths, which adhere to 

 the apex of the root itself. — What a strange union of roots, that 

 of monocotyledons in the main divisions, and of pure acrogens in the 

 minor ! ! 



I cannot help thinking that the secret is hidden in these ramenta, 

 which, as is known, are so universal as obviously to have higher 

 functions than those of mere covering scales. The appearance of 



