398 FILICALES [CH. 



Lancashire as Cyathotrachus alius, but there is no convincing 

 evidence as to the nature of the plant on which it was borne. 



Danaeites. 



This generic name, instituted by Goeppert^, has been used 

 by authors without due regard to the nature of the evidence 

 of affinity to Danaea. The type named by Stur Danaeites 

 sarepontanus" (fig. 291, E) bears small pecopteroid pinnules 

 with ovoid sporangia in groups of 8 — 16 in two contiguous 

 series on the lower face of the lamina. The sporangia dehisce 

 by an apical pore and are more or less embedded in the 

 mesophyll of the segments. No figures have been published 

 showing any detailed sporangial structure, and such evidence 

 as we have is insufficient to warrant the conclusion that the 

 resemblance to Danaea is more than an analogy. 



Parapecopteris. 



Parapecopteris neuropter aides, Grand'Eury. Fig. 290, D. 



The plant described by Grand'Eury* from the Coal-fields of 

 Gard and St Etienne, and made the type of a new genus, is 

 characterised by pinnules intermediate between those of Pecop- 

 teris and Neuropteris* and by the presence of two rows of united 

 sporangia along the lateral veins, as in Danaea and Danaeites. 



Asterotheca. 



Certain species oiPecopteris fronds from Carboniferous strata 

 are characterised by circular sori or synangia consisting of a 

 small number (3 — 8) of exannulate sporangia attached to a 

 central receptacle and free only at their apices. Strasburger^ 

 suggested a Marattiaceous affinity for Asterotheca and Stur"5 

 describes the species Asterotheca Sternbergii Goepp. (fig. 291, 

 C, D) as an example of a Marattiaceous fern. The latter 

 author retains Corda's genus Hawlea"^ for the fertile fronds 



^ Goeppert (362) A. p. 380. 



2 Stur (85) A. p. 221, PI. lxi.; Zeiller (88) A. p. 41. 



3 Grand'Eury (90) A. p. 288, PI. vi. fig. 26. 



* For an account of these genera, see Chap, xxvii. 



6 Strasbnrger (74). « gtur (85) A. p. 183. ? Corda (45) A. PI. lvii. 



