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
Some of the ascidia or pitcher-like formations are due to the cohesion
of the margins of two leaves, as in a specimen of _Crassula
arborescens_, observed by C. Morren.
[Illustration: FIG. 10.--Two-leaved pitcher of _Crassula arborescens_,
after C. Morren.]
The stipules may also be fused together in different ways; their edges
sometimes cohere between the leaf and the stem, and thus form a solitary
intra-axillary stipule. At other times they become united in such a
manner as to produce a single notched stipule opposite to the leaf.
Again, in other cases, they are so united on each side of the stem, that
in place of four there seem only to exist two, common to the two leaves
as in the Hop.
To the Rev. M. J. Berkeley I am indebted for specimens of a curious
pitcher-like formation in the garden Pea. The structure in question
consisted of a stalked foliaceous cup proceeding from the inflorescence.
On examination of the ordinary inflorescence, there will be seen at the
base of the upper of two flowers a small rudimentary bract, having a
swollen circular or ring-like base, from which proceeds a small
awl-shaped process, representing the midrib of an abortive leaf. In some
of Mr. Berkeley's specimens, the stipules were developed as leafy
appendages at the base of the leaf-stalk or midrib, the latter retaining
its shortened form, while, in others, the two stipules had become
connate into a cup, and all trace of the midrib was lost. The cup in
question would thus seem to have been formed from the connation of two
stipules which are ordinarily abortive.
Cohesion of the bracts by their edges, so as to form a tubular
involucre, or by their surfaces, so as to form a cupule, is not of
uncommon occurrence, under natural conditions, and may be met with in
plants which ordinarily do not exhibit this appearance.
=Cohesion of the sepals= in a normally polypetalous calyx renders the
latter gamosepalous, and is not of uncommon occurrence, to a partial
extent, though rarely met with complete. I have observed a junction of
the sepals to be one of the commonest malformations among Orchids,
indeed such a state of things occurs normally in _Masdevallia
Cypripedium_, &c. An illustration of this occurrence is given by Mr. J.
T. Moggridge in _Ophrys insectifera_, in 'Seemann's Journal of Botany,'
1866, p. 168, tab. 47. In Orchids, this cohesion of sepals is very often
co-existent with other more important changes, such as absence of the
labellum, dislocation of the parts of the flower, &c.
[Illustration: FIG. 11.--Gamopetalous flower of _Papaver bracteatum_.]
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