172 MOSSES AND FERNS chap. 



is very easily separated from the dry capsule. Stomata, 

 according to Schimper,^ always are present, sometimes in 

 great numbers ; but Haberlandt " states that these are always 

 rudimentary, and he regards them as reduced forms. No seta 

 is formed, but its place is taken physiologically by the upper 

 part of the axis of the archegonial branch, which grows up 

 beyond the perichaetium, carrying the ripe sporogonium at its 

 top (Fig. 79, E). The upper part of this " pseudopodium " is 

 much enlarged, and a section through it shows the bulbous foot 

 of the capsule occupying nearly the whole space inside it. The 

 ripe capsule breaks through the overlying calyptra, the upper 

 part of which is carried up somewhat as in the higher Mosses, 

 while the basal part together with the upper part of the pseudo- 

 podium forms the " vaginula." 



The disorganised contents of the canal cells, which are 

 usually ejected from the archegonium, in Sphagnum remain in 

 a large measure in the central cavity, and on removing the 

 young embryo from the venter of the archegonium, this muci- 

 laginous mass adheres to it and forms a more or less complete 

 envelope about it, in which are often found the remains of 

 spermatozoids. 



The species of Sphagnum are either monoecious or dioecious, 

 but in no cases do archegonia and antheridia occur upon the 

 same branch. 



The Andrecsacece 



The second order of the Mosses includes only the small 

 genus Andj'ecea, rock-inhabiting Mosses of small size and dark 

 brown or blackish colour. In structure they are intermediate 

 in several respects between the Sphagnaceae and the Bryinese, 

 as has been shown by the researches of Ktihn ^ and Waldner,^ 

 to whom we owe our knowledge of the life-history of Andrecea. 

 They all grow in dense tufts upon silicious rocks, and are at 

 once distinguished from other Mosses by the dehiscence of 

 their small capsules. These, like those of Sphagnum, are raised 

 upon a pseudopodium, but are destitute of a true seta. The 

 capsule opens by four vertical slits, which do not, however, 

 extend entirely to the summit (Fig. 82). This peculiar form 

 of dehiscence recalls the Jungermanniaceae, but is probably only 



1 Schimper (i), p. 55. ^ Haberlandt (4), p. 475. -^ Kiihn (i). 



■1 Waldner (2). 



