4 SCHIZONEURA. 



from India under the name Convallarites, 1 and possibly also as 

 Zeugophyllites* which he classed as Monocotyledons. Schiniper & 

 Mougeot, however, pointed out that these fossils were closely 

 allied to members of the class Equisetales, and their name has 

 consequently been adopted. 



Schizoneura may be defined as follows : — Stems and branches 

 segmented into nodes and internodes. The internodes are ridged 

 and grooved, the ridges and grooves being usually opposite and 

 not alternate at the nodes. The foliar organs consist of lai'ge 

 sheaths without free teeth, which are usually split either into two 

 oval multinerved lobes, or into a number of uninerved segments 

 more or less completely divided. The fructincation consists of 

 compact cones borne terminally. The morphology of the strobilus 

 is unknown. 



Most of the specimens of Schizoneura occurring in association 

 with membei's of the Glossopteris flora appear to be impressions of the 

 external surface of the stem. Others, although possessing features 

 very similar to those above mentioned, appear to be pith-casts, 

 and there is little doubt that at least some Schizoneuras possessed 

 a hollow medullary cavity similar to that of the Calamite. 



Zeiller 3 has recently pointed out that the ridges on the inter- 

 nodes are not always continuous at the node. A similar variation 

 is known among the Calamites, in which the ridges and grooves 

 usually but not always alternate at the node. Zeiller has also 

 compared certaiu specimens of Schizoneura with Calamites ramosus. 



The structure of the leaf -sheaths is very characteristic of 

 Schizoneura. The sheath in the young state is complete, but as 

 it matures it becomes split into a number of segments each with 

 a single nerve, or into two oval lobes with several parallel 

 nerves converging somewhat at the base and apex. The splitting 

 commences at the apex. Similar leaf-sheaths occur in certain 

 living Eqniseta, cf. Equisetum tahnateia (fertile shoots). 



i Brongniart (28 1 ), p. 128. 



2 Brongniart (28'), pp. 118, 121, 175. Brongniart did not publish any figure 

 of this genus, and there has been much confusion as to its nature. The Australian 

 fossils ascribed to Zeugophyllites by McCoy are now known to be Cordaitean 

 leaves (see Arber (02 1 ), p. 18). Morris' specimen, also assigned to this genus, are 

 dow referred to Phcenieopsi* (Seward 1.03 1 ), p. 67). 



:i Zeiller (02 1 ), p. 26. 



