559 



Studies on the Structure and Affinities of Cretaceous Plants. 



By Marie C. Stopes, Ph.D., D.Sc. F.L.S., Lecturer in Paleobotany, 

 Manchester University, and K. Fujii, Ph.D., Assistant Professor of 

 Botany, Imperial University, Tokio. 



(Communicated by Dr. D. H. Scott, F.E.S. Eeceived May 13, — Read 



May 27, 1909.) 



(Abstract.) 



The authors comment on the importance of the work done on the flora of 

 the Palaeozoic period, and the botanical interest that would attach to similar 

 petrifactions of plants from all ages of the Mesozoic period. They have had 

 the good fortune to find excellently preserved material from the Cretaceous 

 of Northern Japan. 



In the present paper they describe 18 plants from this material, which is 

 extraordinarily rich. As hitherto there has been very little known from 

 anatomical material of plants of this age, the present paper is by no means 

 final, but is in the nature of a pioneer chart of the ground. 



The petrifaction of the cells of the plants is often extremely good, though 

 the fragments are not so complete as could be desired. The plant structures 

 include stems, roots, leaves, cones, fern sporangia, and even an Angiospermic 

 flower, the first petrifaction of a flower to be described. The dibris lie 

 together in the nodules in much the same way that the ddbris lie in the 

 Coal-balls of the Palaeozoic, though they are mixed with fragments of shells. 

 The latter are largely Ammonites and serve to determine the age of the 

 petrifactions. 



The flora as a whole represents an interesting mixed flora such as has not 

 hitherto come to light among petrifactions. 



Roughly speaking, the flora seems to have consisted of about one-third 

 Angiosperins, slightly more than one-third Gymnosperms, and the rest of 

 ferns and lower plants. The anatomy of the early Angiosperms being such 

 a desideratum in botany, their presence in the petrifactions renders them 

 doubly interesting, and particularly when they are found in so evenly balanced 

 a mixed flora. 



All the specimens described in this paper were cut in Tokio in the botanical 

 department by the authors. 



The plants described are as follows : — 



Petrosphoeria japonica, gen. et spec. nov. A fungus which has numerous 

 microsclerotia, in the periderm of one of the Angiosperms, Saururopsis. 



