532 PTERIDOSPERMS, ETC. [CH. 



specimens by Miss Benson^ and by Prof. Oliver and Dr Scott 

 has confirmed Stur's interpretation of the appendages at the 

 tips of the fertile pinnae as valves of an indusial or cupular 

 structure. The superficially similar bodies on the fertile pinnae 

 of S. affinis are however true sporangia, and cannot legitimately 

 be included in the genus Calymmatotheca as described by Stur. 

 For this reason Miss Benson institutes a new genus Telangium, 

 the type-species of which, T. Scotti from the Lower Coal- 

 Measures of Lancashire, is based on petrified material. The 

 Scotch species Sphenopteris affinis (= Calymmatotheca affim/is of 

 Kidston) is also transferred to Telangium.; the sporangia are 

 considered by Miss Benson to be microsporangia. This with other 

 species is no doubt correctly included in the Pteridosperms. 

 A complete frond of Sphenopteris affinis, showing a regular 

 dichotomy of the main axes, is represented by an admirable 

 drawing in Hugh Miller's Testimony of the Rocks^. 



Some of the Palaeozoic species of Sphenopteris probably 

 represent the fronds of true ferns, but others are known to have 

 been borne by Pteridosperms. S. Hoeninghansi (fig. 290, C, 

 p. 399) is the foliage of Lyginodendron, and Scott^ speaks of 

 three species, S. dissecta, S. elegans, and S. Idnkii as the leaves 

 of Heterangium. Grand'Eury* has recorded the occurrence in 

 French Coal-Measures of seeds in association with other 

 Sphenopteroid fronds. 



Mariopteris, Diplotmema, Palmatopteris. 



The discovery of sporangia on the fronds of several Pa- 

 laeozoic species of Sphenopteris and Pecopteris has led to the 

 institution of new generic names, which indicate an advance in 

 knowledge beyond the stage implied by the use of those 

 provisional designations based solely on the form and venation 

 of the pinnules. Other names have been created by authors in 

 place of Sphenopteris and Pecopteris on the ground that a 

 striking feature in the mode of branching of ironds is sufficiently 

 important to justify generic recognition even in the absence 



^ Benson (04). 2 Miller (57), Frontispiece. 



3 Scott (052) p, 144 4 Grand'Eury (052). 



