!68 FIL1CES. 



also described as belonging to our present group and as coming from the 

 same locality. In Zippea disticha l also it has been shown that the vascular 

 bundles formed a simple hollow cylinder. It is true that we have only the 

 cast of the stem, but the bundles are preserved inside it as quite thin strips 

 of coal inclosed in the mass of stone ; this is a mode of preservation which as 

 far as I know is observed only in Saxony and Bohemia and near St. Etienne, 

 but which is of frequent occurrence in these districts, especially in the fine 

 clays of Radnitz and the fine-grained sandstones of the Coal-measures of 

 Chomle. 



But there is another series of fern-stems from the Upper beds of the 

 Coal-measures and from the Rothliegende, of which, in exact contrast to 

 those just discussed and by reason of their mode of preservation, we know 

 a good deal of the inner structure but very little of the character of the 

 surface. These stems, which bear the collective name of Psaroniae, are 

 distinguished by a system of circular vascular bundles one inside another 

 like box within box, and show the structure characteristic of recent Marat- 

 tiaceae, and of a few genera, such as Saccoloma, among Cyatheaceae and 

 Polypodiaceae. And now that we know how large a number of Ferns in 

 the period of the Coal-measures had the fructification of Marattiaceae, we 

 have some justification for thinking that we see in the Psaroniae the stems 

 belonging to these fructifications, though their mutual relations cannot be 

 determined in all their details. The silicified Psaroniae of the Rothliegende 

 of Saxony and Bohemia have long been known, having been cut up whole- 

 sale during the last century to make ornaments for all kinds of objects on 

 account of the graceful designs which appear in the sections, so that very 

 few of them are now to be found. The surface is never preserved either in 

 them or in the similar specimens from Val d'Ajol in the Vosges, from Kam- 

 merberg near Ilmenau, from Autun or from St. Eticnne. I have also seen 

 specimens in the same state of preservation in the British Museum from the 

 state of Ohio and from Brazil. They are usually shapeless fragments of 

 small dimensions and weathered on the outside, but longer cylindrical stems 

 of the kind are to be found in a few museums. Fragments of Psaro- 

 niae, in the same state as Zippea disticha, Corda just described, are also 

 met with near Zwickau, Chomle and Radnitz, and are easy to recognise by 

 the peculiar arrangement of the vascular bundles which have been converted 

 into strips of coal. Lastly, Grand' Eury 2 has found in the mines round 

 St. Etienne whole stems in this state of preservation, still rooted in the soil 

 in which they grew, and has figured them under the name of Psaroniocaulon. 

 From these, as also from some of the silicified specimens, we learn that the 

 stems of these plants were long and cylindrical, and that the very gradual 

 conical enlargement which appears in them towards the base is chiefly due 



Corda (1), t. 26. 3 Grand' Eury I , t. n. 



