198 THE BOTANICAL MAGAZINE. [Vo j. xxiv. No. 284. 



the question of the order of appearance of different genera in 

 the history of evolution, especially because it is maintained 

 by Jeffrey and others that the Abietinesa is nearly the oldest 

 type of Conifer ee from which the other families have probably 

 been derived. 



As regards the groups to which Cryptomerian members 

 belong, Jeffrey (1908), from the study of the traumatic 

 ray-tracheids of Cunninghamia sinensis, concludes that the 

 Taxodineas and Cupressineaj did not exist before the very end 

 of the Cretaceous or more probably before the beginning of 

 the Tertiary. By the research of Stopes and Fujii (1910), 

 the presence of a Cunninghamiostrobus species and a Crypto- 

 meriopsis species in the Upper Cretaceous became known, and 

 another Crypto meriopsis species was found by Suzuki, so 

 that we know now that members of Taxodiinae (or Cuppres- 

 sineae) were present at least as early as the Upper Cretaceous. 

 About Cupressineae as known by true genera we have no 

 record yet from our Cretaceous beds, and we do not know 

 whether they appeared for the first time in the Tertiary, 

 or in an earlier period. In this respect, we must note that 

 Cunninghamia, Cryptomeria, and Taxodium were looked upon 

 as Cupressineous than Taxodineous by various authors as Ar- 

 noldi, Lawson, Miyake, and others, chiefly from the study of 

 gametophytes. Miyake (On Cunninghamia sinensis, 1910. p. 

 18) is of the view that Cunninghamia is the most primitive of 

 these three genera, and that Cryptomeria is of more modern 

 origin than the other two. 



These opinions of the authors may be quite reasonable. 

 As the researches of gametophyte of various authors on these 

 points are concerned with living species of the corresponding 

 genus, however, the result cannot be directly extended to the 

 whole genus, especially when we remember that the present 

 representatives of the genera in question are more of the 

 nature of relic plants. 



On the other hand, geological sequence of the first appear- 

 ance of each genus has an important bearing for the dete- 

 mination of these points. As far back as the Upper Cretaceous, 



