47 
Seedling-Structure in Piperaceae. 
elements. Concurrently with these changes the protoxylem of each 
half-bundle gradually twists so as to occupy a dorsal position as 
regards the cotyledon. This rearrangement in the vascular tissues 
of each cotyledonary bundle is strongly marked in the base of the 
petiole of the seed-leaf; the completion and re-fusion being effected 
in the outer cortex of the axis. 
The bundles on entering the stem travel directly to the centre ; 
the opposing groups of phloem fuse together, the protoxylems are 
already in their proper root-position and thus a typical diarch root 
obtains. 
The chief interest in the seedling-structure of this plant 
obviously lies in the fact that the twisting and rearrangement of the 
cotyledonary bundles takes place chiefly in the seed-leaves and thus 
the hypocotyl is, as regards structure, practically non-existent. 
Peperomia maculosa. A single bundle enters the axis from 
each cotyledon, and not only is each of these traces comparatively 
much smaller than the corresponding structure in Piper, but also 
no such rearrangement of the phloem and xylem, as described above 
for the last named plant, has been observed. A little below the 
level of the insertion of the seed-leaves the epicotyledonay strands 
fuse together, into two large collateral bundles with their protoxylem 
groups separated by a few parenchymatous elements. The phloem 
of each of the collateral cotyledon-traces fuses with the corres¬ 
ponding tissue of these epicotyledonary bundles and the xylem 
passing between, occupies a position in contact with the protoxylem 
of the epicotyl bundles and, as far as can be ascertained, plays no 
further part. 
Much of the remaining portion of the main axis does not 
exhibit a really typical root-structure, and it is only near the apex 
that an appearance approximating to that of a normal root, in 
transverse section, occurs. 
The differences between the seedling-structure of these two 
plants are thus of some importance, and require no further emphasis 
here. A complete account of the facts observed in these and other 
plants of the Order will appear in the Annals of Botany. 
