2S4 Sinnott and Bartlett— Coniferous Woods. 



it under that species. It is suggested later in this paper that 

 our Podocarpoxylon is the wood of Xageiopsis. If so, one 

 might reasonably expect to find two or more distinct but simi- 

 lar types of wood corresponding to the different species of 

 Xageiopsis which have been founded upon leaf impressions. 

 On the contrary, it is possible that the difference between 

 Cupressinoxylon [Podocarpoxyloii) McGeei and C. Wardi is 

 due to different growth conditions of the same species, as, 

 indeed, the differences between the leaf impressions might 

 also be. 



The genus Cupressinoxylon was founded by Goeppert* to 

 include woods in which vertical parenchyma is present in some 

 abundance as opposed to Cedroxylon, where this tissue is 

 absent. Gothanf has properly modified the limits of the genus 

 to comprise those forms possessing not only wood parenchyma 

 but also thin-walled, pitless ray cells, structures typical of the 

 members of the Cupressineae to-day. Strictly on this basis our 

 fossil would be placed under Cupressinoxylon, in agreement 

 with Knowlton. Gothan (f), however, has proposed the name 

 Podocarpoxylon for all woods with parenchyma and thin- 

 walled rays which also possess few (usually one or two) lateral 

 ray pits to the crossing field, each with a large outline and a 

 pore varying from a medium-sized vertically or obliquely 

 elongated opening ("podocarpoid") to one which is as large as 

 the outline itself ("eiporig"). This general type is to-clay 

 mainly confined to the members of the Podocarpineae, similar 

 structures outside this group being found only in certain of the 

 soft pines, in Sciadopitys and in Glyptostrobus, in all of which 

 there are other distinguishing characters. Since we have 

 already shown that the ray structures in our fossil vary typi- 

 cally from " podocarpoid " to " eiporig," it should evidently be 

 placed under Podocarpoxylon, if we are to follow Gothan. 

 That it is an actual fossil representative of the Podocarpineae 

 can not, however, be regarded as entirely certain, for some 

 doubt has been cast on the value of Gothams ray characters as 

 definitely diagnostic of podocarpineous woods ; and until our 

 knowledge of the comparative anatomy of this tribe is much 

 more extensive we can not hope to settle the point. Never- 

 thelessj the frequency, among fossil forms, of this wood type 

 with big-pitted rays, in comparison with its relative infrequency 

 at the present clay, is a noteworthy fact. A search, by no 

 means exhaustive, through the literature reveals the following 



*Goeppert, H. E. , Monographie der fossilen Coniferen, Natuurkund. Ver- 

 handl. Holland. Maatsch. Wetensch. Haarlem. Tweede Verzameling, 6e 

 Deel. 1850. 



f Gothan, W. , Zur Anatomie lebender und fossiler Gymnospermen-Holzer, 

 Abli. konigl. preuss. geolog. Landesanstalt, Neue Folge, Heft 44, Berlin, 

 1905. 



