32 



THE PSILOPHYTON FLORA 



[CH. 



Ptilophyton. 

 (Figs. 12-14.) 



Ptilophyton, Dawson^, 

 1878. Main axis (Fig. 12, 

 p. 31) very stout, striated, 

 (the Caulopteris ? Peachii 

 of Salter 2; cf. also the 

 genus Barrandeina) giving 

 off stout lateral decurrent 

 shoots almost at right 

 angles. Branches covered 

 with scale-like emergences. 

 At the apex the axis is 

 freely and closely alternate- 

 ly branched, producing a 

 tuft of shoots ^, the ends of 

 which are circinately coiled 

 (Fig. 18). The ramifications 

 of this tuft bear, apparently 

 on one side, a row of long 

 thin (? filamentous) obscure 

 organs, the nature of which 

 is unknown. They have 

 been described as " tufts of 

 linear bodies^." 



Distribution. Middle De- 

 vonian, ? Bohemia; Upper 

 Old Red, Scotland. 



This genus, markedly 

 different from Psilophyton 

 in habit, is still entirely ob- 

 scure. We may note how- 

 ever that what is probably 



1 Dawson (1878). 



2 Salter (1859), p. 407, Fig. 14 

 on p. 408; Kidston (1902) de- 

 finitely states that Caulopteris 

 Peachii, Salter, is the stem of 

 Ptilophyton Thomsoni, Dawson. 



3 Carruthers (1878), PI. 137. 



Fig. 13. Ptilophyton Thomsoni, Dawson. 

 The terminal portions of axes possessing 

 emergences. Type specimen from the 

 Upper Old Red of Scotland. (Reduced 

 about |.) After Carruthers (1873). 



