CARBONIFEROUS LYCOPODS AND SPHENOPHYLLS. 125 



single sporangium, which thus hangs parallel to the axis. 1 

 (Fig. 23.) 



Although the late Professor Williamson was the first to 

 describe the internal structure of the cones of Sphenophyttum, 

 they were described under the name 

 of Volkmannia, and to Zeiller is due 

 the credit of identifying the Volk- 

 mannia Dawsoni, Will., as the fructi- I- 



fication of Sphenophyttum. 2 On this 

 subject he published a preliminary note 

 in 1892. 3 This was followed by his Fig . 23. — Sphenophyttum 

 admirable memoir entitled, " Etude sur cuneifolium, Sternb. sp. 

 la constitution de V appareil fructijicateur Arrangement of the 

 des Sphenophyttum." sporangia. 



In this memoir Zeiller describes a number of cones of 

 S-phenophyllum cuneifolium. Sternb. sp., from the French and 

 Belgian Coal Fields. The paper is accompanied by an excellent 

 and most instructive series of figures taken from photographs of 

 the specimens. M. Zeiller has clearly shown, it appears to me, 

 that the Volkmannia Daicsoni, Williamson, is the fructification 

 of Sphenophyllum cuneifolium, Sternb. sp., and, though there are 

 some points awaiting further elucidation, the main structural 

 features have been clearly demonstrated. There seems to have 

 been generally three sporangia borne on each bract, which form 

 a corresponding number of whorls of sporangia surrounding the 

 axis. Two or four circles of sporangia seem to occur in some 

 cases. 



The sporangiophores or pedicels all spring from the saucer-like 

 collar of the bracts, and, as seen in specimens showing the 

 internal structure, their point of origin formed a circle round the 

 axis; they were thus laterally placed to each other. 



The sporangiophores, however, immediately become free, and 

 their length varies according to whether the sporangiophore 



1 Williamson ' ' On the Organisation of the Fossil Plants of the Coal 

 Measures," Memoir V., Phil. Trans., 1874, p. 41, seq. Under name of 

 Volkmannia Dawsoni, ibid., Vol. CLXXX1I. , p. 225, seq., 1891, and 

 references given above. 



2 Zeiller, fctude sur la constitution, &c., I.e., pp. 20-21. 



3 Sur la constitution des epis de fructification du Sphenophyttum cuneifolium, 

 Coinptes rend us, July 11, 1892. 



