﻿Vol. 64.] PERMO-CAEBONIFEROTJS PLANTS FROM VEEEENIGING. 119 



LePIDODENDEON VEREENIGINGENSE, Sp. DOV. (PI. X, figS. 1 & 2 ; 



and text-fig. 8.) 



The fragment shown in PL X, fig. 2 (7*3 centimetres long) 

 represents a sandstone-cast exhibiting spirally-disposed leaf-cushions 

 approximately 1*8 centimetres in length. It is probable that the 

 actual surface is not preserved, but the amount of decortication 

 must have been trifling : each leaf-cushion consists of a raised 

 upper portion, the leaf -scar region, characterized by a short groove 

 which we interpret as marking the position of the vascular bundle 

 and possibly also of the parichnos connected with the leaf. The 

 converging ridges below the prominent leaf-scar indicate the 

 probable limits of the leaf-cushions, the form of which cannot be 

 made out in detail in the absence of more perfect specimens. 



The impression represented in PI. X, fig. 1 (18 centimetres by 

 3 cm.) is probably that of a stem very similar to, or perhaps iden- 

 tical with, that shown in fig. 2. Spirally-disposed and somewhat 

 indistinct areas cover the surface of the fossil ; their shape and size 

 suggest Lepidodendron leaf-cushions, and this comparison receives 

 support from the appearance presented by the upper part of some 

 of the areas (text-fig. 8), which shows traces of a median promi- 

 nence and of two lateral depressions in the position of the leaf- 

 bundle and the two arms of the 

 parichnos. A zone (PL X, fig. 1 A), 

 2 centimetres deep, is characterized by 

 crowded areas of much smaller size, 

 similar in shape to the leaf-scars of a 

 Sigillaria. The most probable expla- 

 nation of this interruption in the regular 

 sequence of elongated leaf-cushions is, 

 that it affords evidence of some zonal 

 variation in the nature of the scars, 

 such as we are familiar with in cer- 

 tain species of Sigillaria, but which 

 is uncommon in Lepidodendron. An 

 example of zonal variation has been 

 figured by Dr. Potonie in Lepidodendron 

 Volkmannianum, Sternberg, from the 

 Culm of Magdeburg ^ ; in that stem 

 the elongated cushions are succeeded 

 at intervals by narrow zones of shorter 

 cushions, similar to those on the 

 Vereeniging specimen. Specimens de- 

 scribed by Mr. Carruthers ^ as Lepido- 

 dendron notlmm, Unger, from Queensland, also exhibit a similar 

 zonal variation in the size of the scars. 



We are disposed to regard the fossils figured in PL X as 



Pig. 8. — Lepidodendron 

 vereenigingense : le.af- 

 cushion (x 4)' 





1 Potonie (01) p. 115, fig. 71 & (05) pt. iii, p. 51. See also Nathorst (94) 

 pi, viii, fig. 2. 



Carruthers (72) p. 353 & pi. xxvi. 



