Manchester Memoirs, Vol. I. (1906), No. 10. 7 



tral parts is so poor that there seemed no prospect of 

 being able to see the actual growing point. There is a 

 small block remaining, however, in which we can feel 

 confident that the apex existed whether it is now preserved 

 or not. The sections of this region reveal the fact that 

 the parts attained a considerable size prior to the 

 differentiation of the xylem, but they threw no light on 

 the question of the position of the protoxylem or of the 

 direction of differentiation of the metaxylem. 



4. Branching. 



The main axis, or rhizome, runs the length of the 

 specimen without branching directly, or giving off any 

 structure of the same order as itself Surrounding the 

 main axis are the numerous petioles which it gives off in 

 rapid succession. In each transverse section there are 

 several petioles closely associated with it, though it is 

 impossible to be sure whether or not they have entirely 

 separated from the main cortex, as the outer layers of 

 both axis and petioles are wanting, of these, three are 

 generally undoubtedly within the main axis cortex. At 

 the time when the two cortices are certainly distinct the 

 diameter of the petiole is slightly less than that of the 

 main axis, and about one quarter that of the largest 

 petiole preserved. 



The pJiyllotaxy appears to be exceedingly near to, if 

 not actually f, and the spiral is a close one. The reasons 

 that there is any doubt about the matter are, (i) the 

 rather uncertain preservation, (2) the fact that both axis 

 and petioles bend, though but slightly, independently and 

 at different angles. The plant with which it is natural to 

 compare this, viz., Tubicaulis Solenites, is described by 

 Stenzel ('89) as having a spiral of ]^ further out, and ^t 

 or y\ near the axis, but in the case of my specimen, to 



