284 STUDIES IN FOSSIL BOTANY 



form of the sporangia of which the sori are composed, 

 while it approaches the genus Kaulfussia in the circular 

 grouping of the sporangia, and finally resembles the 

 genus Angiopteris in the fact that the sporangia become 

 free in their upper part. In the mode of dehiscence of 

 the individual sporangia, Scolecopteris agrees with all 

 three genera mentioned, but the similarity to Marattia 

 is again the most striking, to which it also bears the 

 greatest resemblance in the structure of the sori." 



So far as the pedicellate sori are concerned, the 

 agreement is especially close with the subgenus 

 Eupodium of Marattia. 



In the genus Dactylotheca of Zeiller, another of the 

 Pecopteris group (see Fig. i09,C),the sporangia are some- 

 what similar in form to those of Scolecopteris. They are, 

 however, completely independent of one another ; each 

 sporangium is placed singly over a lateral vein. The 

 line of dehiscence can be recognised, but there is no 

 trace of an annulus ; it is mainly on this ground that 

 Dactylottieca and various other genera with separate 

 sporangia have been placed in the Marattiaceae. For 

 example, in the genus Renaultia of Zeiller 1 (see Fig. 1 09, 

 B), the ovoid sporangia are independent, isolated, or 

 grouped in small numbers at the extremity of the 

 nerves. In this case there is an indication of a 

 rudimentary annulus, like that of the recent Angiopteris, 

 at the apex of the sporangium. Renaultia, Zeill., was 

 the fructification of certain species with fronds of the 

 Sphenopteris type. 



1 Hapalopteris of Stur, whose genus Renaultia is quite different, having 

 typical synangia. The nomenclature of these fructifications is lamentably 

 involved. 



