Manchester Memoirs, Vol. lix. (191 5), No. 3. 11 



Selected sections from a complete series of transverse 

 sections through one plant are represented in outline in 

 Fig. 2 A — L. In A the plane of section passes through 

 the stock above the level of the stem apex, so that 

 in the centre the apical depression with young leaves 

 projecting from its sides is cut across. The next 

 section (B) is just below the level of the apex, so that the 

 central hole has disappeared, the section passing through 

 the procambium above the summit of the stele. The 

 latter is distinct and lignified at the level of C> but has no 

 secondary zone of prismatic tissue. In these figures the 

 tvvo-lobed nature of the stock is recognisable, but it is 

 clear that the leaf traces to the functional and young 

 leaves stand symmetrically around the apex and summit 

 of the stele in a complicated spiral. At the level of 

 Fig. 2 D the secondary zone produced by the meristem 

 is well marked. The bases of leaf-traces evident around 

 the stele belonged to the leaves of former seasons. The 

 whole of the cortex belongs to the shoot, no roots being 

 evident at this level. In the section shown in Fig. 2 E 

 the cortex belongs mainly to the shoot region, but 

 beneath the groove root-traces are seen in the cortex, and 

 the bases of roots are visible on the split surface extend- 

 ing from the groove. The level of the section is above 

 the point of origin of the highest root-traces from the 

 central vascular axis. In F, however, at a slightly lower 

 level the tips of the upward extensions of the half-moon- 

 shaped rhizophoric region of the woody axis are cut 

 across and these are more marked in G. The root-traces 

 are seen extending outward from these, while young roots 

 not yet exposed on the surface have their tips pointing 

 towards the plane of the split It will be noted that the 

 outer level of the rhizophoric xylcm coincides with the 

 line of meristem round the stem-stele. So far the outline 



