3 2 4 



STUDIES IN FOSSIL BOTANY 



Corynepteris is at present only known from impres- 

 sions ; we may compare with it a genus, Diplolabis, 

 Renault, 1 which has been studied entirely in petrified 

 material. The stem is unknown, but the structure of the 

 petiole indicates affinity with Zygopteris. In both the 

 species described, D. forensis, from the Upper Coal- 

 measures, and D. esnostensis, of Lower Carboniferous 

 age, the fructifications are described as synangia, with 



Fig. 120. — Asterochlaena laxa. Part of transverse section of stem with surrounding 

 petioles. The deeply lobed stele is shown, also the leaf-traces and the curved 

 bundles in the petioles. Nat. size. After Stenzel. From Tansley. New 

 Pliytologist. 



from three to six sporangia attached to a common 

 central receptacle. The sporangia differ from those of 

 Corynepteris in having no differentiated annulus. It is 

 also probable that the synangia were borne on a naked 

 rachis, and not on an expanded lamina, as in the 

 former genus. 



Two genera, of which only the vegetative anatomy 

 is known, may be shortly mentioned. Anachoropteris, 



1 Flore fossile d'Autun et d'Epinac, t. ii. p. n. 



