and on the Sexes of Mosses. 481 



that the embryo requires no preparation to enable it to perforin its func- 

 tions. 



But, taking into full consideration the facts above narrated, we cannot 

 but conclude that in the Cellulares,<x provision similar to that of the pistillum 

 in Vasculares, does not exist, — the former being capable of reproduction by 

 the mere ejection of its pollen or sporules on the soil. 



Professor Lindley has drawn an ingenious analogy between the parts of 

 fructification in Mosses, and the flower of Vasculares. He argues, that the 

 peristome and calyptra are modified leaves, obeying the received laws of 

 morphology. Not having an opportunity of examining the proofs, which he 

 draws from examples in the cotyledonous plants, I cannot enter on this sub- 

 ject with any chance of either disproving or confirming his opinions. I can, 

 however, bear testimony to the opinion that the calyptra is a modified leaf. 

 Any one who had seen the young leaves of Tortula ruralis growing amongst 

 the pistilla would be struck with the similarity of their appearance. If the 

 small portion of lamina at the base of the excurrent nerve were folded 

 inwards, and united at the margin, it would be almost impossible to distin- 

 guish the leaf from the calyptra. Dr. Greville, in his beautiful Scottish 

 Cryptogamic Flora, has unintentionally given a good proof of this fact. His 

 figure of the calyptra of Leshea polyantha has two nerves at the base, opposite 

 the fissure, precisely similar to those which are found at the base of all the 

 leaves in the plant. 



Since this paper was read to the Society, I have been informed by Mr. Brown 

 that Dr. Mohl has recently published some " Observations on the Development 

 and Structure of the Sporae of Cryptogamous Plants;" a translation of that 

 part which relates to the Mosses he has most kindly furnished me with. 

 Dr. Mohl describes the cavity between the columella and columellar mem- 

 brane as being occupied, in an early state, by an extremely delicate cellular 

 tissue, the cells of which lie in horizontal rows, and contain small granular 

 masses, the rudiments of the future sporse. In most Mosses, he states, the 

 sporse are four in each mother cell, and they are arranged in a tetrahedral 

 union. He fancied that, in some of the cells, he discovered more than four 



VOL. xvu. 3 R 



