XXXII] PROTOPITYS 213 



As Solms-Laubach says, it is highly probable that each leaf- 

 trace, which forks close to its exit from the primary xylem, became 

 further subdivided before reaching the leaf. Morphologically, 

 Protopitys is of special importance as a type possessing characters 

 that indicate a connexion with Conifers or Cordaitean genera, 

 notably the structure of the secondary wood, while the presence of 

 foliar gaps is a feature reminiscent of Ferns. The primary xylem 

 resembles that of some of the Palaeozoic arborescent Lycopodiales, 

 but in Protopitys the interruptions in this tissue are due to the 

 emission of leaf-bundles, whereas in the discontinuous primary 

 xylem of some Sigillarias 1 the gaps have no connexion with 

 leaf -traces. Moreover the distichous leaves of Protopitys and 

 the larger, branched, leaf-traces are other distinguishing features. 

 The pitting of the primary xylem is like that in the Lycopodiales 

 and Filicales, while that of the secondary wood shows a closer 

 approach to the coniferous type. A comparison may also be made 

 with the transversely elongated pits of Cladoxylon Kidstoni 2 . 



A piece of wood agreeing anatomically with the Silesian 

 species of Protopitys has been found in the Yoredale rocks of 

 England 3 . 



The peculiarities of the genus have been emphasised by Solms- 

 Laubach by the institution of a family-name Protopityeae : the 

 genus is essentially a generalised type exhibiting in the structure 

 of its stem both Filicean and Coniferous features. The bordered 

 pits differ from those in recent Conifers in their flatter form, 

 but in this respect they exhibit a closer agreement with the trans- 

 versely stretched pits of Xenoxylon phyllocladoides Goth. 4 , a 

 Mesozoic species. 



1 Vol. n. p. 212, fig. 200, A, B. 



2 See page 206. 



3 In the form of the pits on the tracheids and in the structure of the medullary 

 rays the English species (as represented in Dr Kidston's Collection) agrees very 

 closely with Goeppert's type. 



4 Gothan (07 2 ) p. 10. 



