Vegetable Teratology: An Account of the Principal Deviations from the Usual Construction of PlantsMasters, Maxwell T. (Maxwell Tylden)
Science
Vegetable Teratology: An Account of the Principal Deviations from the Usual Construction of Plants
Masters, Maxwell T. (Maxwell Tylden)
Plants -- Abnormalities
For convenience sake the teratological alterations of size may be
divided into those which are the result of increased growth and those
which arise from diminished action. It will be seen, therefore, that in
these instances it is the bulk of the organs that is increased, not
their number; moreover, their development or metamorphosis is not
necessarily altered. In connection with increased size an alteration of
consistence is so frequent that the two phenomena are here taken
together. It will be borne in mind that the changes of consistence from
membranous to succulent or woody are very frequent in the ordinary
course of development. They may also occur as accidental phenomena, or
the normal conditions of any particular flower or fruit may be exactly
reversed, the usually succulent fruit becoming dry and capsular, and so
forth.
PART I.
HYPERTROPHY.
The term hypertrophy may serve as a general one to comprise all the
instances of excessive growth and increased size of organs, whether the
increase be general or in one direction merely. General hypertrophy is
more a variation than a deformity, unless indeed it be caused by insect
puncture or the presence of a fungus, in which case the excessive size
results from a diseased condition. For our present purpose hypertrophy
may be considered as it affects the axile or the foliar organs, and also
according to the way in which the increased size is manifested, as by
increased thickness or swelling--intumescence, or by augmented
length-elongation, by expansion or flattening, or, lastly, by the
formation of excrescences or outgrowths, which may be classed under the
head of luxuriance or enation.
As size must be considered in this place relatively, it is not possible
to lay down any precise line separating what are considered to be the
normal dimensions from those which are abnormal.
In practice no inconvenience will be found to accrue from this inability
to establish a fixed rule, and we may say that an hypertrophied organ is
one which, from some cause or other, attains dimensions which are not
habitual to the plant in its usual, healthy, well-formed state.
It will be seen that under this general head of hypertrophy, increase of
size, however brought about, is included; thus, not only increase in
length, but also in thickness; alterations of substance or consistence,
no less than of dimensions, are here grouped together. The alterations
of consistence resulting from an inordinate development of cellular,
fibrous, or ligneous tissue, are, of course, strictly homologous with
the similar changes which occur, under ordinary circumstances, during
the ripening of fruits or otherwise.
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