372 STUDIES IN FOSSIL BOTANY 



a transverse section belonging to a series cut from one 

 of the original specimens, a stem about . to give off a 

 branch, which is still in connection with the main axis. 

 A peculiar feature of the branching is that two of the 

 leaf-traces in the pericycle of the main stem pass out 

 into the branch, one on each side, and supply its first 

 two leaves ; the third leaf of the branch receives a 

 trace from its own stele, passing out between the two 

 former. 



In some specimens branching of the stem has been 

 found to be often repeated at short intervals, and in 

 these cases it is always axillary, though it is not certain 

 that this condition was constant. It is quite possible 

 that the occurrence and mode of branching may prove 

 to characterise distinct species still included under the 

 collective name L. oldhamium} 



Various individual anomalies^ in the anatomical 

 structure have been observed ; the most frequent and 

 interesting consists in the formation of secondary wood 

 and bast, with inverted orientation, in the pith, im- 

 mediately within the normal ring of bundles. The 

 anomaly, in fact, is the same as that occurring in certain 

 species of Tecoma and lodes among recent Dicotyledons. 

 It is evident that the anomalous cambium, giving rise 

 to these medullary formations, was sometimes, if not 

 always, continuous, through the trace -gaps, with the 

 normal cambial zone. Thus it occasionally happened 

 that each segment of the wood became completely 

 surrounded by a zone of cambium, and grew in 

 thickness on its own account, so that such a stem 



1 The branching of Lyginodendron has recently been fully investigated 

 by Miss Brenchley, whose results are not yet published. 



