494 STUDIES IN FOSSIL BOTANY 



paratively slender, branched stem of the Rhaetic 

 Anomozamites (see Chap. XIII.) offers an analogy, 

 and as Ptychoxylon, at any rate, is known to have 

 branched pretty freely, it is quite possible that M. 

 Renault's interpretation is the right one. It seems 

 not impossible, however, that the whole structure may 

 represent a single compound leaf or sporophyll, or even 

 a single fertile pinna, the bodies immediately bearing 

 the seeds being of the nature of leaflets. In the latter 

 case, we should have a sporophyll more complex than 

 that of any recent Cycad, and its affinities would 

 probably be with the Pteridosperms ; on M. Renault's 

 interpretation, the fructification would represent a nearer 

 approach to the cones of the Zamieae. In any case the 

 fossil is of the greatest interest, and it is much to be 

 hoped that specimens with structure preserved may yet 

 be discovered. 



Whether these leaves and fructifications belonged to 

 Cycadoxyleae or not, it is probable that the stems in 

 question (or some of them) were those of plants which 

 had already passed the boundary (at most a very in- 

 definite one) between Pteridosperms and Gymnosperms. 



Protopityeae 



The Lyginodendreae, Calamopityeae, and Cycado- 

 xyleae appear to form one group, though by no means 

 a linear series. The next type of Cycadofilices to be 

 considered is represented by a remarkable and isolated 

 form, our present knowledge of which is due to the 

 investigations of Count Solms-Laubach. This is the 

 Protopitys Buchiana of Goppert, a very ancient fossil, 



