25(5 



THE AMEHICAN NATURALIST [Vol. XLIV 



Paleozoic gymnosperms, particularly with the Cordaitales, and 

 in this respect has the strongest claim to be considered as the 

 oldest representative of the coniferous stock. 



In a recently published article, Jeffrey considers certain 

 abietineous features, such as resin canals of the secondary wood, 

 or the occurrence of marginal ray tracheids, which are found as 

 abnormalities in certain species belonging to the sequoiineous 

 and cupressineous tribes of conifers. 10 He reaches the conclu- 

 sion that these abnormal abietineous features of the tribes in 

 question are not indications of the derivation of the Abietinea? 

 from them, as has been inferred by Penhallow and others, since 

 recent structural paleobolanieal inwst i^ntions show that the 

 Abietinea? are immeasurably older geologically than the se- 

 quoiineous or cupressineous tribes. The conclusion is arrived 

 at that the resin canals or ray tracheids, which sporadically occur 

 in the woods of S<<in<>ia, TJmi/a. S< latin/iil Cioniiiialniniia. etc. 

 indicate that the Sequoiinea? and Cupressinea? came off from the 

 Abietinea? in the late Mesozoic or early Tertiary, after the 

 latter had developed marginal ray tracheids in their wood rays. 



The general result of numerous recent investigations on the 

 anatomy of living and extinct conifers is to show that the two 

 coniferous tribes which have to-day diametrical polar distribu- 

 tion are both very old, reaching back as far as the Paleozoic, that 

 now widely separated geographically and anatomically they once 

 flourished side by side in the northern hemisphere and were 

 connected phyloerenetically by a series of transitional forms. 

 The preponderance of evidence moreover seems to vouch for the 

 greater age of the Abietinea?. The more modern and cosmopoli- 

 tan tribes, the Sequoiinea\ Cu press in ere, Taxinea?, and Podo- 

 carpinea? appear further to have been derived from abietineous 

 forebears at a comparatively recent epoch. Even the Podocar- 

 pinea? of present characteristic antarctic range, appear from Miss 

 Gerry's interesting investigations, to have come from the 

 general abietineous stock and not from the Araucarinea?, as has 

 been the conclusion of those who have recently investigated the 

 microgametic structures of the araucarians and podocarps, since 

 the latter possess liars of Sanio, which never occur in the Arau- 

 carinea?. 



E. C. Jeffrey. 



Haevakd University. 



Traumatic Ray-Tracheids in Cunnighamia sinensis," Ann. Bot.. 



