44 THE PSILOPHYTON FLORA [CH. 



This type is again wholly obscure and many examples of it 

 no doubt represent small fragments of some of the preceding 

 genera above discussed. 



SPOROGONITES. 



Sporogonites, Halle, 1916. Isolated stalked sporangia; spor- 

 angia obovoid or clavate, 69 mm. long and 2-4 mm. broad; 

 apex rounded, base attenuated. 



Distribution. Lower Devonian, Roragen, Norway. 



This type has been recently described by Halle 1 from impres- 

 sions from Roragen as examples of a Bryophytic sporogonium. 

 He claims to have made out by maceration methods that the 

 lower part of the capsule was "sterile throughout, the upper 

 part consisting of three different zones : a wall of several layers 

 of cells, a thick sporogenous tract and a sterile central columella 2 ." 

 The spores are tetrahedral, globular, 0-020-0-025 mm. in diameter, 

 with cutinised walls. 



An attentive examination of the description of these specimens 

 given by Halle, has left us entirely unconvinced that any valid 

 grounds exist for regarding these sporangia as sporogonia. In 

 the absence of well-petrified material, it appears to us that the 

 present distribution of the spores may well be secondary and 

 not original. The fact that the wall of the sporangium, as we 

 prefer to call it, is several layers in thickness has no bearing on 

 the matter. The walls of the sporangia of Psilophyton ( = Rhynia), 

 as Kidston and Lang have shown, are also multi-layered, and 

 to our eyes there is nothing about that genus which suggests 

 affinities with the Bryophyta. The presence of a columella we 

 regard as entirely unproven, and we doubt very much if the 

 presence of such an organ, even if it undoubtedly existed, could 

 be established from material preserved in the manner of the 

 Norwegian specimens. That Sporogonites may be something more 

 complicated than a sporangium with a simple uni-layered wall 

 is quite* possible, but even admitting this, it appears to us that, 

 on the present evidence, its relationships are to be sought for 



1 Halle (1916). 



2 Ibid. p. 27. 



