The present work, while dealing with the origin
of the regenerated organs, pursues the subject further
and following the developmental anatomical features
of these members subsequent to their initiation, shows
how their internal construction is influenced in the
first place by the internal organisation of the parent
axis from which they arise, and secondly (in the case
of roots) by the external environmental conditions in
which they are produced.
That the normal ontogenetic processes of an organ
have/an influence on its regenerative phenomena is shown,
especially in the case of leaf propagation, and in
view of such a fact it has been found necessary to
describe in some detail the differentiation of tissues
occurring in the root and shoot as they pass from
their embryonic condition to the attainment of maturity.
These previously mentioned papers have shown how
remarkably plastic this plant is when considered from
the viewpoint of vegetative propagation; the present
paper shows an equally remarkable plasticity in internal
tissue organisation, and as the facts emerge it
becomes very suggestive that the two sets of phenomena
cannot be considered apart.
Lastly, several points encountered during the
investigation of leaf propagation suggested that an
interesting comparison might be made between the
anatomical changes occurring therein and the anatomy
of the seedling. Accordingly, seedlings were
raised, and as these exhibit some points of interest
other than those for which they were originally
intended, a fuller account of their development is
given than was originally considered necessary.