CONTRIBUTIONS FROM THE PHANEROGAMIC LABORATORIES 

 OF HARVARD UNIVERSITY. NO. 58. 



THE HISTORY, C0:MPARATIVE ANATOMY AIsFD EVOLU- 

 TION OF THE ARAUCARIOXYLOxN TYPE. 



By Edward C. Jeffrey. 

 Part IV. 



The present article will be devoted to the consideration of the 

 structure of the pith and the relations of the foliar trace in woods of 

 the Araucarioxylon type and nearly allied Araucarian lignites. Gothan 

 in his second memoir on arctic woods, which deals with the fossil 

 ligneous remains of the island of Spitzbergen, makes the statement 

 that the Cretaceous fossil, which the present writer has described under 

 the name Araucariopitys *^ and considered on the basis of its general 

 organization to belong to the Araucarian alliance, cannot be so referred 

 on account of the abietineous character of its rays and on account of 

 the sclerotic septa in the pith, a character in his opinion likewise ex- 

 clusively Abietineous.*^ The writer has shown in the first article of the 

 present series, that the presence of Abietineous rays is by no means 

 necessarily an indication of Abietineous affinity, especially in the case 

 of Mesozoic woods. It will be his aim to demonstrate in the present 

 communication that sclerotic diaphragms in the medullary region are 

 equally fallacious criteria of Abietineous affinities. Professor Seward 

 has adduced the persistent leaf trace of the living genera Agathis and 

 Araucaria and of true x\raucarioxyla from the Mesozoic deposits, as 

 an argument for the antiquity of the Araucariineae and for their 

 relationship with the extinct Lycopodiales, which he considers like- 

 wise as characterized by leaf-traces persistent for a long time in the 

 secondary wood. The writer will attempt to show in the present article 

 that on generally accepted biological principles the leaf trace was not 



42 Jeffrey, Araucariopitys, a new genus of Araucarians, Bot. Gazette 44, pp. 

 435-444. 



43 Gothan, Die Fossilen Holzreste von Spitzbergen, Kung. Svensk. Veten- 

 skap. Handlingar, Bd. 45, No. 8, Uppsala u. Stockholm (1910). 



