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
Moquin's second objection is founded upon the fact that, in certain
fasciated stems, the branches are not increased in number or altered in
arrangement from what is usual; but however true this may be in
particular cases, it is quite certain that in the majority of instances
a large increase in the number of leaves and buds is a prominent
characteristic of fasciated stems.
Another argument used by the distinguished French botanist to show that
fasciated stems are not due to cohesion of two or more stems, is founded
on the fact that a transverse section of a fasciated stem generally
shows an elliptical outline with but a single central canal. On the
other hand, if two branches become united and a transverse section be
made, the form of the cut surface would be more or less like that of the
figure 8[Symbol: 8 turned 90 deg.], although in old stems this may give
place to an elliptical outline, but even then traces of two medullary
canals may be found. This argument is very deceptive, for the appearance
of the transverse section must depend, not only on the intimacy of their
union, but also on the internal structure of the stems themselves. When
two flowers cohere without much pressure they exhibit uniting circles
somewhat resembling the figure of 8[Symbol: 8 turned 90 deg.], but when
more completely combined they have an outline of a very elongated figure,
and something similar is to be expected in herbaceous stems. Even the
elongated pith of a transversely cut, woody, fasciated stem only marks
the intimate union of several branches, and Prof. Hincks, whose views
the writer entirely shares, has noticed instances of the union of two,
and of only two, stems where the internal appearance was the same as in
other fasciations.
Moquin, moreover, raises the objection that it is unlikely that several
branches should become united lengthwise in one plane only, and,
further, that in the greater number of fasciations all the other
branches which should be present are to be found--not one is wanting,
not one has disappeared, as might have been anticipated had fusion taken
place. In raising this objection, Moquin seems not sufficiently to have
considered the circumstance that the buds in these cases are in one
plane from the first, and are all about equal in point of age and size.
The last objection that Moquin raises to the opinion that fasciation is
the result of a grafting process is, that in such a case, examples
should be found wherein the branches are incompletely fused, and where
on a transverse section traces of the medullary canals belonging to each
branch should be visible. The arrangement of leaves or buds on the
surface should also in such a case indicate a fusion of several spiral
cycles or whorls. To this it may be replied that such cases are met with
very frequently indeed. A figure is given by De Candolle[15] of a stem
of _Spartium junceum_ having several branches only imperfectly
fasciated.
Public-domain text, read in full here on John Shaqi.
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