284 CONIFERALES INCEBTAE SEDIS [CH. 



the Tylodendron casts is also shown in specimens from the Lower 

 Permian of Saxony in the Chemnitz Museum^. Casts similar to 

 those described as Tylodendron and Schizodendron were recorded 

 by Schleiden in 1846 and referred to a new genus Endolepis : he 

 believed them to be casts of the pith-cavity of some Dicotyledonous 

 stem. Examples of Endolepis have been described by Schenk and 

 more recently by Fliche^ who discusses the history of the genus 

 and on the ground of priority adopts Schleiden's name in prefer- 

 ence to Schizodendron. It is, however, preferable to retain 

 Schizodendron for the larger casts with periodic swelUngs. The 

 smaller type represented by Endolepis has in several instances 

 been found in connexion with the foliage of Voltzia^ (fig. 748) and 

 it is questionable if a special designation is needed. In the form 

 of the raised areas on the surface of the cast Schizodendron and 

 Endolepis appear to be identical : while suggesting the advisability 

 of retaining the former name I recognise that the Permian and 

 Triassic casts may belong to stems which are closely allied or even 

 generically identical. 



The structure of the wood of Schizodendron speciosum is of the 

 Araucarian type ; the tracheids have 1 — 3 rows of contiguous and 

 alternate pits on the radial walls and the medullary rays are 

 usually uniseriate. Potonie compares the pith-casts of the Palaeo- 

 zoic stems with those of recent species of Araucaria and Agathis : 

 the pith of the recent species is much smaller but in both fossil 

 and recent medullary casts there are periodic swellings where the 

 presence of scars, sometimes in a whorl or pseudo whorl*, marks 

 the position of branches. The pith-cast of a recent Cycad (fig. 398, 

 p. 29, Vol. III.) bears a general resemblance to Schizodendron: in 

 Araucaria the medullary rays are narrower and so produce 

 narrower raised areas on a pith-cast. 



Schizodendron Cowardi (F. E. Weiss). 



Prof. F. E. Weiss^ has recently described an interesting example 

 of Schizodendron which throws some fresh light on structural 

 features. The specimen was found in Cheshire but not in situ 

 and nothing is known as to its geological age ; it consists of a 



1 Sterzel (00). ^ p^ghe (10) p. 212, Pis. xix., xx. 



= Seward (90). See also page 290. 



* ZeiUer (92") A. PI. xv. fig. 5. = Weiss, F. E. (IS^). 



