104 The Katuealtst. 



I have not attempted to give a history of the development of the 

 capsule and its spores ; I have slides illustrative of this matter in all 

 its phases, and must let that part of the subject form some future 

 paper. 



This is an imperfect sketch of the normal development of mosses, 

 but most, if not all the mosses appear to have the power of reproducing 

 themselves by means of cellular bodies called gemmie ; sometimes 

 these occur in the axils of certain of the leaves, as in Tetraphis ; 

 sometimes as in Aulacomnlon, at the top of an abortive seta ; and at 

 other times, some of the marginal cells of a leaf will begin to protrude, 

 and this protruded cell, by repeated cell divisions, lengthens out into 

 a protonema-like body, as in Orthoirichum Lyellii, and other Orilio- 

 trichcB. In this neighbourhood 0. Lyellii must be perpetuated by 

 this means alone, as the plant never fruits with us. These buds, or 

 gemmae, on germinating give rise to a protonema similar to that 

 formed by the spore. In some of the marsh Hypna I have seen 

 plants formed from even the central cells of a leaf ; this is a case not 

 unfrequent with Rypnum giganteim — in fact, in these j^lants nature 

 has amply provided for their perpetuation. 



In the commencement of my notes, I mentioned that there were 

 analogies in the development of ferns and mosses ; these I hope I 

 have made clear, but perhaps a brief recapitulation may not seem 

 intrusive. 



The structure of the archegon'umi of mosses is similar to that of 

 ferns. In ferns it is that part of the prothallium in the interior of 

 which " the embryo of the frond-bearing plant originates." " In 

 both large groups of higher cryptogams there is a cell which 

 originates freely in the large central cell of the archegonium^ by 

 repeated division of which free cell, the fruit of the moss and the 

 frond-bearing plant of the fern are produced." In both cases, however, 

 this free central cell remains unchanged, and the archegonium is no 

 further developed unless at the time of the opening of the top of the 

 archegonium spermatozoids find their way to it. It is necessary that 

 these facts should be borne in mind, because unless we acknowledge 

 the true sexuality of these plants (which is the fact I have been 

 endeavouring to establish), we are not in a position to discuss this 

 question of hybridization. 



Hofmeister considers that the fruit of the moss is analogous to the 

 fern plant with its fronds, and that the leafy stem of the moss is 



