XXIl] 



DACTYLOTHECA 



405 



pinnae are subtended by two Aphlebiae (fig. 293, A) appressed 

 to the rachis, like the delicate leaves of the recent fern Tera- 

 tophyllum aculeatum (see page 301). The sporangia (0"5 — 0"65) 

 are oval and exannulate and are attached parallel to the lateral 

 veins ; they may occupy the whole of the space between the 

 midrib and the edge of the pinnules. This species occurs in the 

 Upper, Middle, and Lower Coal-Measures of Britain, reaching 



"^ ^ftJ^QA. 





Fig. 292. Dactylotheca plmnosa . (After Kidston. Slightly reduced.) 



its maximum in the Upper Coal-Measures. The aphlebiae 

 undoubtedly served to protect the young fronds, as shown by a 

 specimen figured by Kidston (fig. 293, B) ; they may also have 

 served other purposes, as suggested by the above comparison 

 with Teratophylluni, in the mature frond. Lindley and Hutton 

 regarded the aphlebiae as leaves of a fern climbing up the 



