V THE ANTIIOCEROTE^ 147 



to the formation of the axial bundle of elaters in Pellia, 

 and that in NototJiylas as in the Jungermanniaccai, the arche- 

 sporium arose from the inner of the cells formed by the first 

 periclinal walls, and not from the outer ones. That this is not 

 true for A^. orbicularis is shown beyond question from sections 

 of both the older and younger sporogonium, and it would be 

 extremely strange if the other species should differ so radically 

 from this one as would be the case were Leitgeb's surmise 

 correct. 



The wall of the capsule does not develop the assimilative 

 apparatus of the AntJioceros capsule, and stomata are completely 

 absent from the epidermis. The inner layers of cells are more 

 or less completely disorganised, and they probably serve to 

 nourish the growing spores, which here, of course, are corre- 

 spondingly more numerous than in AntJioceros. As there, the 

 sterile cells form a series of irregular chambers in which the 

 spores lie. At maturity these sterile cells separate into irregu- 

 lar groups (Fig. 74, C). Their walls are marked with short 

 curved thickened bands, yellowish in colour like the wall of the 

 ripe spores. At maturity the capsule projects but little beyond 

 its sheath, and opens by two valves. In some species, e.g. N. 

 melanospora, the capsule often opens irregularly. 



The Anthoceroteae form a most interesting series of forms 

 among themselves, but are also of the greatest importance in 

 the study of the origin of the higher plants. Unquestionably 

 NototJiylas represents the form which comes nearest to the 

 other Liverworts, but until the other species are investigated 

 further we shall have to assume that the type of the sporo- 

 gonium is essentially different from that of the lower Hepaticas, 

 and corresponds to that of the other Anthoceroteae. The 

 primary formation of the columella and the subsequent differ- 

 entiation of the archesporium occur elsewhere only in the 

 Sphagnaceae. From NototJiylas, where the archesporium con- 

 stitutes the greater part of the older sporogonium, and the 

 columella and wall are relatively small, there is a transition 

 through the forms with a relatively large columella to Dendro- 

 ceros, where the spore formation is much more subordinated and 

 a massive assimilative tissue developed. In NototJiylas the 

 secondary growth of the capsule at the base, while it continues 

 for some time, is checked before the capsule projects much 

 beyond its sheath. In Dendroceros the growth continues much 



