FILICES. 173 



sclerenchyma is less conspicuous in the small Gottingen stem ; every section 

 through one of its leaf-stalks shows in the concavity of a crescent-shaped trans- 

 verse section of a leaf-trace two other smaller roundish leaf-trace-sections. 

 The determination of these objects as stems of Osmundaceae rested at first 

 on the habit only, which does certainly agree absolutely with that of Os- 

 munda. But now that leaves have also been found in the same freshwater 

 quartz rocks in Hungary which have been declared to belong to Osmunda l , 

 we must certainly allow that there are good grounds for this determination, 

 though it has not been proved that the stems have the characteristic course 

 or the collateral structure of the bundles of Osmundaceae. The habit alone 

 would scarcely be sufficient, as is shown by a small and remarkable stem 

 from the Rothliegende of Chemnitz, which was first described by Cotta 2 , 

 and has received from Corda 3 the name Asterochlaena Cottai, Corda. A 

 full description of this fossil is to be found in Goppert 4 . I have myself 

 had opportunity of seeing a transverse section of it in the British Museum 

 which came from Cotta, and other specimens in the municipal collection 

 at Chemnitz. On superficial examination it recalls Osmunditae, but it is 

 distinguished from that group by one very important particular ; instead of 

 a vascular bundle-ring in its axis, it has a single central bundle of con- 

 siderable dimensions and with an irregularly stellate transverse section, the 

 rays of which are variously curved and sometimes also split into diverging 

 branches. This is a structure without a parallel in living Ferns, but some- 

 thing like it occurs apparently in another small stem from the Upper 

 Devonian beds (Portage group) of New York, which Dawson 5 has de- 

 scribed and named Asteropteris noveboracensis, Daws. Here too there is 

 a star-shaped xylem bundle in the axis with long rays, which may be 

 simple or regularly branched. A peripheral sclerenchymatous tissue in- 

 closes leaf-traces with a peculiar biscuit-shaped transverse section. Dawson 

 has unhesitatingly placed this genus of his with Ferns, but from his own 

 statejnents it is not impossible that it may belong to Lycopodiaceae ; and 

 Unger's 6 Cladoxylon, with which he compares it, is usually ranked with 

 that group. Cladoxylon itself will be considered in a later chapter with 

 Lycopodia. 



Lastly, some very small herbaceous stems with simple structure are 

 seen in the genera Zygopteris and Botryopteris, the fructifications and leaf- 

 stalks of which have already been considered. That the stems in question 

 do belong to these genera is well ascertained, for Renault 7 has found them 

 in actual connection with the characteristic leaf-stalks. In Zygopteris the 

 vascular body lies in the uniform parenchyma, which is traversed by 

 numerous leaf-traces, in the form of a closed ring surrounding a pith which 



1 Schimper (1), vol. i, p. 678. 2 Cotta (1). 3 Corda (1), p. 81. Goppert (3), p. 41 ; 



t. 9, f. i. " Dawson (4), t. 12. 6 Unger (5). 7 Renault (2, 4, 5, 7). 



