Xl] SPHENOPHYLLUM SPECIOSUM. 411 



For a more complete systematic account of the different species 

 the student should consult such works as those by Coemans and 

 Kickx\ Zeiller, Schimper, and others. 



4. Sphenophyllum speciosum (Royle). Fig. 111. 

 1834. Trizygia speciosa, Eoyle^. 



The species shown in fig. Ill has been usually described as 

 a separate genus Trizygia, a name instituted by Royle in 1834 

 for some Indian fossils from the Lower Gondwana rocks of 

 India ^ Zeiller^ has lately pointed out the advisability of 

 including this Asiatic type in the genus Sphenophyllum. The 

 slender stem bears verticils of cuneate leaves in three pairs at 

 each node, the anterior pair being smaller than the two lateral 

 pairs. The characteristic Sphenophyllum venation is clearly 

 seen in the enlarged leaf, fig. Ill, B. 



A B 



Fio. Ill, Sphenophyllum speciosum (Royle). 

 A. Nat. size. B. enlarged leaf. 

 From the Raniganj Coal-field, India. (After Feistmantel.) 



The inequality of the members of a single whorl, which 

 characterises this Indian plant, is sometimes met with in 



^ Coemans and Kickx (64); Zeiller (80), (88); Schimper (69). 



'' Royle (39), p. 431. 



:« For other figures of this plant, vide Feistmantel (81), PU. xi. a and xii. a. 



* Zeiller (91). 



