Note ■ 
483 
lack of material, but it may be presumed that the bundle eventually returns to the 
periphery and establishes connexions with the neighbouring bundles at some node 
below. 
The course of this bundle suggests, to some extent, that taken by the leaf-traces 
in some members of the Piperaceae, where, it will be recalled, the leaf-trace bundles 
form a system of medullary bundles during a part of their course in the stem. 
It is not suggested that the anomalous bundle in Helianthus traverses a complete 
internode before passing into the pith, as is the case for example in Peperomia . 
2. The development of secondary tissue in the vascular ring in the neighbourhood 
of the abnormal bundle is of considerable interest. 
A relatively small number of secondary elements have been laid down, and con- 
sequently there has been very little displacement of the primary tissues (Figs. 2 and 3). 
A reference to the diagrams in Fig. 1 will make clear the sequence of events. 
At the stage illustrated in Figs. 1, a, and 3, the bundle is not far removed from the 
