TI] THE TWO FLORAS 11 



LOWER OLD RED SANDSTONE (Forfarshire, Perthshire, etc.) 1 : 

 Psilophyton princeps, Dawson 2 , 1859. 

 P. ornatum, Dawson 3 , 1871. 

 P. robustius, Dawson 2 , 1859. 

 Arthrostigma gracile, Dawson 4 , 1871. 

 Zosterophyllum myretonianum, Penhallow 5 , 1892. 

 Parka decipiens, Fleming 6 , 1831. 

 Cryptoxylon Forfarense, Kidston 7 , 1897. 



The great peculiarity of the Old Red Sandstone flora of 

 Scotland, so far as it is at present known, is its wealth of members 

 of the Psilophyton flora and its poverty in examples of the 

 Archaeopteris flora in its highest stage. 



Ireland. The Upper Devonian flora of the South of Ireland 

 includes several species of Archaeopteris (A. hibernica, Forbes 8 ' 11 

 andA.Tschermaki, Stur 9 ), BothrodendronKiltorkense, (Haught. 10 ), 

 and Sphenopteris Hookeri 11 , (Bailey). No members of the older 

 archaic flora have yet been recognised. 



England. The Upper Devonian of Devonshire 12 has yielded 

 Sphenopteridium rigidum, a fragmentary Sphenopteris, a unique 

 fructification, Xenotheca, a Telangium and a doubtful leaf of 

 Cordaites; there are no traces of archaic forms. 



Belgium. The Upper Devonian rocks of Belgium 13 contain 

 Archaeopteris, Sphenopteridium condrusorum, and a species of 

 Sphenopteris, associated with Barinophyton, and possibly 

 Psilophyton. The Lower Devonian flora 13 of the same country is 

 very obscure. Arthrostigma (the so-called Lepidodendron Gas- 

 pianum) and Psilophyton probably occur. 



Germany. In the Upper Devonian of Hesse-Nassau 14 , Spheno- 

 pteridium rigidum, an Archaeopteris (the Sphenopteris densepin- 

 nata of Ludwig) and a Rhacopteris (the Cyclopteris furcillata, 

 etc., of Ludwig and Triphyllopteris of Schimper) are possibly 

 1 Hickling (1908). 2 Dawson (1859). 



3 Included hitherto as a variety of Dawson's P. princeps. 



4 Dawson (1871), p. 41; Kidston (1894), p. 102. 



5 Penhallow (1892), p. 9, Pis. I, II. 



6 Fleming (1831); Don and Hickling (1917). 



7 Kidston (1897). 



8 Carruthers (1872); Kidston (1888) and (1906). 



9 Johnson (1911 2 ). 10 Johnson (1913). 



11 Kidston (1906). * 2 Arber and Goode (1915). 



13 Crepin (1874) and (1875); Gilkinet (1875 1 ), (1875 2 ). 



14 Ludwig (1869); Potonie (1901). 



