d.

The terms adopted in the present work are, for the most part, not
necessarily intended to convey any idea as to the organogenetic history
of the parts affected. Where a single organ, that is usually entire,
becomes divided the term Fission is used; in cases where parts of the
same whorl become isolated, the word Dialysis is employed, and in the
same sense in which it is generally used by descriptive botanists, and
where the various whorls become detached one from the other, the
occurrence is distinguished by the application of the term Solution.

FOOTNOTES:

[66] 'Bull. Acad. Belg.,' t. xix, part iii, 1852, p. 315.

CHAPTER I.

FISSION.

When an organ becomes divided it receives at the hands of descriptive
botanists the appellations cleft, partite, or sect, according to the
depth of the division; hence in considering the teratological instances
of this nature, the term fission has suggested itself as an appropriate
one to be applied to the subdivision of an habitually entire or
undivided organ. It thus corresponds pretty nearly in its application
with the term Chorisis or "dedoublement," or with the "disjonctions qui
divisent les organes" of Moquin-Tandon.[67] It is usually, but not
always, a concomitant with hypertrophy, and dependent on luxuriance of
growth.

It must be understood therefore that the term, as generally applied,
does not so much indicate the cleavage of a persistent organ, as it does
the formation and development of two or more growing points instead of
one, whence results a branching or forking (di-tri-chotomy) of the
affected organ. In some instances it seems rather to be due to the
relative deficiency of cellular, as contrasted with fibro-vascular
tissue.

=Fission of axile organs.=--This condition is scarcely to be
distinguished from multiplication of the axile organs (which see). A
little attention, however, will generally show whether the unusual
number of branches is a consequence of the development of a large number
of distinct shoots, as happens, for instance, when a tree is pollarded,
or of a division of one. M. Fournier[68] gives as an illustration the
case of a specimen of _Ruscus aculeatus_ in which there occurred a
division of the foliaceous branches into two segments, reaching as far
as the insertion of the flower, but no further. He also mentions lateral
cleavage effected by a notching of the margin, the notch being anterior
to the flowers and always directed towar