FOSSIL PLANTS. 47 



of Nematophycus has been replaced in the process of 

 mineralisation by a typical Celluloxylon structure. 



In 1850, Goeppert described a plant stem from the 

 Carboniferous limestone of Falkenberg, in Silesia, under 

 the name of Protopitys Buchiana} A recent number of 

 the Botanische Zeitung contains a paper by Solms-Laubach 2 

 in which a clear case is made out for the removal of 

 Goeppert's plant from the Conifers?, in which it was 

 originally placed, to the PteridopJiyta. Most of the frag- 

 ments of Protopitys which have their minute structure 

 preserved are small pieces of secondary wood ; by the 

 examination of these and some few more complete ex- 

 amples, Count Solms has been able to demonstrate the 

 following anatomical details. The secondary xylem shows 

 the general character of coniferous wood ; regularly disposed 

 rows of polygonal pitted tracheids, with fairly numerous 

 medullary rays generally one cell and sometimes two or 

 three cells deep. The pits in the tracheid walls suggest 

 a form intermediate between the usual bordered pits of 

 conifers and the scalariform pits of fern tracheids. The 

 secondary wood on careful microscopic examination shows 

 no indication of annual rings. As frequently happens in 

 fossil plants, the transverse section of a stem shows distinct 

 concentric lines suggestive of ordinary rings of growth, but 

 these on higher magnification are found to be simply the 

 expressions of disturbances in the elements of the xylem. 



In the pith some very interesting features are recorded ; 

 instead of the normal plan in which the primary medullary 

 rays terminate in the cells of the pith, there is a closed 

 central strand which is parenchymatous in the central part, 

 and, at the periphery, is composed of irregularly arranged 

 tracheal elements. A transverse section of the pith shows 

 an elliptical form with two ear-shaped swellings at the ends 

 of the major axis. The tracheal sheath surrounding the 

 parenchymatous centre consists of one to three rows of 



1 Monograph. Foss. Conif., p. 229. PI. xxxvii., figs. 4-7. PI. xxxviii., 

 figs. 1, 2. 



- Bot. Zeitung, Heft 12, 1893, p. 197. 



