22 ARKIV FÖR BOTANIK. BAND 17. NIO 1. 



transferred to Didyophijlliuii by Xathorst,. Avho,. however, pro- 

 jjosed to keep the generic name for the species Th. Brauniana 

 Popr. Tlii.s species was not figured by Porr ( 1 863), but later on 

 Schenk, in his »Flora der Grenzschichten», published illustra^ 

 tions of both Th. Brauniana and Th. Miinsleri. As Xat- 

 HOEST (1878) has pointed out, however, .Schenk's figures of 

 Th. Brauniatia represent t^ o different species, the one described 

 by Popp and a second type named by Xathor.st Th. Schenki. 

 In Ills description of Th. Brauniana, Popp writes »Die 

 Sporangien sind über die ganze untere Seite zerstreut, sitzend, 

 und' von einem vollständigen vielgliederigcn Ringe eingefasst 

 ...... Schenk's description of Th. Brauniana does not give 



any additional information on the sori and sporangia. Of the 

 real Th. Brauniana he does not figure any sporangia. The 

 sporangia in pi. 18, fig. 2, which belong to Th. Schenli, show 

 a rather indistinct annulus that cannot be traced to its whole 

 length. 



Thauinatopteris Schenki Nath. (PI. 2, figs. 25, 26.) 



The material of this species from the Pvhaetic beds of the 

 coal mine of Stabbarp in Scania contains well preserved fertile 

 specimens. The sori and sporangia have been described and 

 figured ])y Xathorst (1907). Xathoest gives the number of 

 sporangia in each sorus as about 9 (8 — 10) and their diameter 

 as 0,20 — 0,25 mm. I have more often found the diameter to be 

 0,3 mm. or even more. 



The sx^orangia figured by Xathorst (1907, pi. 2, figs. 16 

 17) are seen edgeAvise, and the whole extent of the annulus 

 cannot be followed. In pi. 2, figs. 25, 26, of the j^resent paper, 

 therefore, I have given two photograjihs of the sporangia as 

 seen from the side, perpendicular to the annulus. The annulus 

 appears to be somewhat twisted, as in Dictyojjhylhim exile, 

 and in no case was it j^ossible to trace its whole length. It is 

 probably not quite complete, in so far as both ends do not 

 meet, and on the whole it seems to be very similar to that 

 of Dichjophyllum exile. 



The sf)orangia can easily' be removed from the matrix, 

 and it was possible in some cases to isolate them from each 

 other and to count the spores after the usual treatment. For 

 the five sporangia of which the spores could be counted, the 



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