XLV] 



SCHIZODENDRON 



283 





Schizodendron speciosum (Weiss). One of the casts figured by 

 Weiss and assigned by him to this species has a length of 70 cm. 

 and at intervals of about 30 cm. shows periodic swellings where it 

 assumes a barrel-shaped form. Pieces of wood attached to some 

 of the casts were investigated by 

 Dippel who found that they agreed 

 anatomically with Araucarian stems. 

 Weiss considered his specimens to be 

 generically identical with casts figured 

 by Eichwald 1 from Kussia as species 

 of Schizodendron and Angiodendron. 

 Potonie, while uncertain as to the 

 close agreement with some of Eich- 

 wald's fossils, regarded Tylodendron 

 as identical with Eichwald's Schizo- 

 dendron, and Zeiller 2 , in view of this 

 agreement, adopted the older name 

 Schizodendron. The latter author 3 

 formerly believed Tylodendron, as 

 described by Weiss, to be distin- 

 guished from Schizodendron by the 

 apical occurrence of the slit on the 

 so-called leaf-cushion in contrast to 

 the basal slit in Schizodendron, but 

 Potonie 4 proved that in bbth cases 

 the median groove extends up the 

 lower portion of each projecting FIG. 746. Schizodendron specio- 

 area from its base and represents sum - (After Potonie; f nat. 

 an out-going leaf-trace; he also 



demonstrated that Schizodendron is a pith-cast, the tapered 

 areas being the inner ends of medullary rays. In some specimens 

 the casts afford some indication of a discoid pith. The relation 

 between the wood and the pith-casts is also very clearly shown 

 in a section of a petrified stem of Permian age from Prince 

 Edward Island described bv Miss Holden 5 . The true nature of 



1 Eichwald (60) B. PI. xvm. 

 3 Ibid. (80) p. 263, PL v. 

 5 Holden, R. (13) p. 245. 



2 Zeiller (92 2 ) A. p. 102. 

 4 Potonie (88). 



