VII THE BRYINEAL 217 



course this does not assume a direct connccliejn between 

 Sphagnum and any known form among the Anthoceroteae. 

 There are too many essential differences between the two to 

 allow any such assumption : but that the two groups have 

 come from a common stock seems reasonably certain, and the 

 structure of the capsule in Sphagmun points to some form 

 which like AntJioceros had a highly-developed assimilative 

 system. This is indicated by the presence of stomata, which, 

 although functionless, probably were once perfect, and make it 

 likely that with the great increase in the development of the 

 gametophyte the sporophyte has lost to some extent its 

 assimilative functions, which have been assumed by the 

 gametophyte. 



AndrecEa, both in regard to the gametophyte and the sporo- 

 phyte, is in many ways intermediate between Sphagimin and the 

 other Mosses. The resemblance in the dehiscence of the 

 sporogonium to that of the Jungermanniaces is probably 

 accidental. It may perhaps be equally well compared to the 

 splitting of the upper part of the capsule into four parts, in 

 Tetraphis, although in the latter it is the inner tissue and not 

 the epidermis which is thus divided. 



If this latter suggestion proves to be true, then there would 

 be a direct connection of Andre(Ea with the stegocarpous 

 Bryineae, and not through the cleistocarpous forms. These 

 latter would then all have to be considered as degraded forms 

 derived from a stegocarpous type, unless, with Leitgeb, we 

 consider them as a distinct line of development leading up to 

 the higher Bryineae, entirely independent of the Sphagnaceae, 

 and with Archidiuni and Ephemeruin as the simplest forms. 

 His comparison of these forms with Notothylas, however, cannot 

 be maintained with our present knowledge of that genus, and 

 more evidence is needed before his view can be accepted ; but 

 the possibility of some such explanation of the cleistocarpous 

 Bryineae must be borne in mind in trying to assign them their 

 place in the system. 



The objections to considering Buxbaumia a primitive form 

 have been already given, and it is not necessary to repeat 

 them. 



