68 ON THE FOSSIL FLORA OF THE COAL DEPOSITS OF AUSTRALIA, 



scars. But we never see isolated scars, whereas isolated diaphrag- 

 mata of Equisetum of all sizes are very common in the upper Lias 

 of France and Germany (Ores bigarre and Keuper)." But the 

 most convincing thing of all is that we find such diaphragmata loose 

 in the stems of living Equiseta. In places where these plants grow 

 abundantly in the loose damp mould around the roots abundance 

 of these disks of every character may be seen. 



In the present species it will be noticed that there is only one 

 circle of radiated lacunas, and a central tube which corresponds to 

 the second. In the figure of Lindley and Hutton there are two 

 concentric circles and no central hollow. In the figures given by 

 Feistmantel of Equisetum rajmahalensis * (Equisetites, Morris and 

 Oldham), at fig. 3 there is represented a diaphragm which is on 

 the same plan as our fossil . There is an outer radiating circle of 

 lacunas and an inner central hollow. The species are, however, 

 different. The outer ring of lacunas was in this fossil small and 

 bead-like, and it does not appear in the impressions, because it is 

 along the outer line of spaces that the separation of the diaphragm 

 took place. Traces of it may be seen in those specimens which 

 are well preserved, and where the diaphragm is seen in position, 

 which is rare. One such instance is given in fig. 2 of Feistruantel's 

 plate, already referred to. 



The size and shape of these diaphragmata show what were the 

 dimensions and form of the stems. They were perfectly round, 

 and the internal furrows were close together, about 25 in a stem 

 two- thirds of an inch in diameter. There are steins broader than 

 that, but they have been flattened out. In the largest specimen 

 in my possession there are three or four internodes, and some of 

 them are as long as twice the width of the stem. 



The line of division between the connate teeth of the sheath can 

 be traced to the base of the internode. The leaves are thus seen 

 to be longer than the width of the stem, and they are marked at 

 their margins by a fine raised line. They are of equal width for 



* Memoirs of the Geological Survey of India. Paleontologia Indica. Fossil 

 Flora of the Gondwana system. Oldham and Feistmantel, Vol. I., plate 11, 

 fig. 3. 



