FERNS— FRUCTIFICATIONS 281 



side of each sac. Certainly some of the preparations 

 show quite clearly that the sporangia are separate 

 down to the base of the synangium. Forms with the 

 sporangia distinctly separate are, however, regarded by 

 Stur as constituting a different genus, to which he has 

 given the name Hawlea (see Fig. 109, H). It thus 

 appears that in Asterotheca and allied fructifications, 

 the cohesion of the sporangia was much less perfect 

 than in the living Marattiaceous genera Kaulfussia, 

 Danaea, and Marattia. 



A number of species with fronds of the Pecopteris 

 type are known to have borne the fructifications of 

 Asterotheca. They are chiefly characteristic of the 

 Upper Coal-measures and Permian. 



The genus Grand' Eurya of Stur is interesting from 

 its resemblance to the recent Angiopteris. The fructi- 

 fications in question were first described by Renault 

 from silicified specimens, and referred by him to two 

 species of Pecopteris, P. oreopteridia and P. densifolia} 

 The sporangia are inserted along either side of the 

 lateral veins of the fertile pinnules, and appear to be 

 quite free from each other. There is, however, some 

 indication of a grouping of the sporangia in fours. 

 Thus in GrandEurya Renaulti of Stur (attributed to 

 P. oreopteridia by Renault) there are usually eight 

 sporangia belonging to each lateral vein, and forming 

 apparently two quadrate groups of four each. On 

 account of the latter arrangement, Zeiller attributes 

 these species to the genus Asterotheca ; in Grand'Eurya 

 there seems to be no formation of synangia, but Zeiller con- 

 siders that this condition, as in Hawlea, is only due to age. 

 1 Renault, Cours de Bot. Fossile, t. iii. 1883, p. no, Plate 19. 



