657 
Macroglossum Alidae , Copeland. 
A section taken a short distance below the apex (b) shows the leaf- 
trace belonging to the cotyledon, in which the first tracheary tissue can be 
seen, and near it a second group of cells forming the trace for the second 
leaf. 
The primary leaf-trace shows a small group of reticulate tracheides 
near its inner side and may be described as collateral, in this respect 
resembling Danaea . Sections taken still lower down show the coalescence 
of the two leaf-traces into a single strand, which is continued directly into 
the primary root. This axial bundle, after the fusion of the leaf-traces is 
complete, has the tracheary tissue forming a short band in cross-section 
occupying the middle of the bundle (e). The stele of the primary root is, 
usually at least, diarch, and probably derives its two xylems from the first 
and second leaf-traces respectively. 
Text-fig. i. a, Transverse section passing through the apical region of a young sporophyte, 
in which the second leaf (Z, 2 ) was just recognizable, st., stem, x 180. B, Section taken a short dis- 
tance below the apex, showing the separate traces of the first and second leaves, x 50. C, Central 
region of b. x 180. u, e, Sections taken further down, showing the union of the leaf-traces, x 50. 
Text* fig. 2 shows two longitudinal sections of a sporophyte in which 
the second leaf was already pretty well advanced, and the third could also 
be seen. In A the second leaf is cut almost in the median plane, and the 
single vascular bundle is clearly seen. In B the section traverses the 
cotyledon, and shows the continuity of the vascular bundles of the cotyledon 
primary root. The junction of the second leaf- trace with the primary 
vascular strand is also shown. At this stage the second root is evident, 
arising close to the base of the second leaf-trace, with which its vascular 
cylinder is united. C shows the stem-apex of this sporophyte. The large 
oblong cell in which the nucleus is shown is probably the single initial, 
but the segmentation appears to be very irregular. Below the apex there 
