OF LOWER GREETS T SAXD PLANTS. 227 



walls of the ray-cells arc very characteristic, being single, large* 

 oval or nearly circular pits, placed one per tracheid-field, some 

 of which show very distinct circular borders. 



AFFINITIES. The pitting and character of the walls of the 

 medullary rays, coupled with the other features of the wood, are 

 so characteristic of the modern Podocarpus that I have no hesi- 

 tation in placing the species in the genus Podocarpoxylon. In 

 the irregular bore and the chains of pitting of its tracheids, 

 however, our fossil is unlike, not only any fossil, but any living 

 Podocarpoid plant with which I am acquainted. Series of pits 

 adjacent or almost adjacent to each other are found in several 

 living arid fossil species (among fossils, for example, in Bracliy- 

 phyllum macrocarpum, see Jeffrey, 1906) ; but in all such cases 

 the adjacent pits do not form definite chains, but merely places 

 where locally the pits, elsewhere isolated, are more closely 

 crowded. 



Owing, doubtless, to their arrangement, the rims of Sanio are 

 not seen in this fossil a point which certain botanists would at 

 one time have taken to be proof of Araucarian affinity (e .g. Holden, 

 1913 B). On other grounds there are reasons to anticipate an 

 ancestral relationship between the Podocarpineae and Arau- 

 carinea} ; whether the pitting of the tracheids of this early 

 Podocarpoid form is an indication of it, is open to discussion. 



V. 13191. Type-specimen. Decorticated splint of wood from 

 the core of a woody branch or trunk. Present dia- 

 meter 6x3 cm. and 13 cm. length. The position of 

 the centre of the stem indicates that it must have 

 had a minimum diameter of 8 cm. when alive. The 

 wood is free from matrix, and shows the woody 

 texture very well in various directions ; there are a 

 few teredo-borings. 



V. 13191 a. Figured, PL XXI, fig. 1. Transverse section of the 

 above, somewhat broken in cutting. The position of 

 the pith and primary wood is clear, but both are 

 entirely decayed. Growth- rings can be clearly seen, 

 particularly with the low power. The tracheids, 

 medullary ray-cells, and xylem-parenchyma are all 

 well preserved. 



Q2 



