32 ART. 14-K. YENDO: 



thickening of the wall is accompanied by the formation of canals therein. 

 The canals radiate from the center of the cells, some continuous to 

 the canals of the neighbouring 1 cells and some ending at the middle 

 lamella, cf. Cor. verae Japon. PL 1. fig. 20, which illustrate the cross 

 in id the longitudinal sections of the medullary portion of an old 

 geniculum.. 



The bordered pits are also modified by the thickening of the wall. 

 At an early stage, only the canals which are modification of the pits 

 are to be seen. But in the further advanced stage, a new formation 

 of canals takes place by the thickening of the walls ; so that we can 

 not distinguish the canals of genetically separate origin. 



These remarks do not apply to the genicula of Amp. stelligera, 

 although they are built up with a number of zones. The cortical cells 

 in these genicula remain persistent from the beginning and the zonal 

 cells grow rapidly and increase in their number by transverse division. 

 The cortical cells also accompany the growth and the multiplying of 

 the cells. It is not certain how the primitive genicular are transform- 

 ed from the calcified articuli. The presence of the extragenicular 

 portions suggests the similarity of the mode of the genicular formation 

 with that of the unizonal genicula. But already in a pretty young 

 genicula, several zones of the periclinal ceils have been clearly observed 

 (tig. 8). I was not able to trace the origin of the genicula in the 

 species, as the apical portions of the dried material are always due to 

 the destruction of the cellular arrangement while imbedding in the 

 paraffin. This must he kept for future study, until we have preserved 

 material from fresh plants. 



One thing; which we must not omit mentioning here is that the 

 primary genicula of the ramuli of Amp. stelligera aie not directly 

 connected with the articular cells but with the cells of the axial 

 geniculum. Some of the zonal cells of the axial geniculum travel 



