PROCEEDINGS OF THE SOCIETY. 519 1 



admitted to be an ancient group of Ferns, well represented in Lower as 

 well as Upper Carboniferous times, and not at present betraying any 

 symptoms of Spermophytic affinities. The family was chiefly known 

 from structural specimens, very few impressions, showing the habit, 

 having been as yet referred to it. 



Mr. Newell Arber, in a recent discussion at the Linnean Society,* 

 proposed to establish a group Primofilices to include the Botryopteridese 

 and other primitive Ferns of Palaeozoic age. The object of the present 

 communication was to give a few illustrations of this ancient race of 

 Ferns, to which Professor Lignier had also called attention.! 



The Botryopteridea? proper were first described, beginning with the 

 type genus Botrypteris, now represented by at least two British species 

 in addition to the French form on which Renault founded the genus. 

 Fructifications probably referable to the English species were shown, 

 the multiseriate annulus being a characteristic feature of the genus. 



The genus Zygopteris was next considered, and attention called to 

 the presence of central tracheides internal to the main ring of wood ; 

 besides Renault's species, the British representatives Z. Grayi and 

 Z. corrugata were described ; the former showing axillary branching, as 

 in the recent Hyrnenophyllaceas, while in Z. corrugata the ramification 

 was found to be rather of the nature of a dichotomy. The structure 

 of the scale-leaves, or aphlebiae, described by Renault and Stenzel in 

 Continental species, was demonstrated for the first time in a British 

 form, Z. corrugata. % Sporangia with a very broad annulus were 

 described, which might probably belong to species of Zygopteris, though 

 it was not yet possible to compare them in detail with the well-known 

 fructifications discovered by Renault. 



A new genus from the Lower Coal-Measures of Lancashire was then 

 described, remarkable for possessing radially seriated wood, apparently 

 of a secondary character. In other respects the structure had much in 

 common with that of Zygopteris corrugata, the new genus, for which the 

 name Botrychioxylon was proposed, being related anatomically to 

 Zygopteris somewhat as Botrychium to Ophioglossum among recent 

 Ferns. This was the first time that evidence of secondary growth in 

 thickness had been obtained among the Botryopterideas. 



After two or three other examples of this family had been given, 

 Dr. Scott described certain annulate Fern-sporangia,§ borne on the 

 pinnules of a Sphenopteroid lamina, which were not uncommon in the- 

 calcareous nodules of the British Lower Coal-Measures. In some aspects 

 the appearance of these sporangia was wonderfully Polypodiaceous, 

 but transverse sections of the annulus showed that it was two cells in 

 breadth. There was nothing to connect this fructification immediately 

 with the Botryopteridese, but it might be placed provisionally within 

 the broader limits of Mr. Arber's Primofilices. 



An instance of spores caught in the act of germination within a 



* See New Phytologist, April 1906. 



t Equisetales et Sphenophyllales. Leur Origine filicineene commune. Bull. 

 Soc. Linn, de Normandie, 1903. 



J They were also present in Zygopteris Grayi, contrary to the opinions expressed. 

 in the author's Studies in Fossil Botany, p. 284. 



§ Since named Pteridotheca Williamsoni. 



