ther. The column and ovary of this flower were in their normal
condition.

Cohesion of two or more segments of the perianth is frequently
associated with displacements of this nature: thus, in a flower of
_Dendrobium nobile_, a diagram of which is given at fig. 48, the
uppermost sepal was coherent with one of the lateral ones, and at the
same time diminished in size, and, as it were, dragged out of position.
All the other organs of the flower are also more or less displaced,
forming a minor degree of the change already alluded to, and which
Morren termed speiranthy. The changes will be better appreciated by
comparing them with fig. 49, a diagram showing the natural arrangement
of parts in this species.

[Illustration: FIG. 48.--Plan of malformed flower of _Dendrobium
nobile_.]

[Illustration: FIG. 49.--Plan of natural arrangement in _Dendrobium
nobile_. The x x represent processes of the column, perhaps rudiments of
stamens.]

Sometimes the displacement seems consequent on hypertrophy of one of the
parts of the flower, the disproportionate size of one organ pushing the
others out of place. This was the case in a violet, fig. 50, in which
one of the sepals _s_ was greatly thickened, and the petals and stamens
were displaced in consequence.

[Illustration: FIG. 50.--Plan of flower of violet showing displacement
of petals, &c. At _b_ was a rudiment of a stamen.]

It is curious to observe in many of these cases that the transposed
organ not only occupies the place of a suppressed or abortive organ,
but frequently assumes its colour, and, to some extent, its function.
This has been alluded to in the case of the leaf of _Gesnera_ (see p.
88) and in Orchids this replacement seems to be very common; thus, in
addition to the cases before mentioned, in a flower of an Odontoglossum,
for which I am indebted to Professor Oliver, the two lateral sepals were
united together and occupied the position of the labellum, which was
absent. A similar occurrence happens occasionally in _Lycaste Skinneri_,
thus recalling the structure of _Masdevallia_, where the labellum is
normally very small. The arrangement in Lycaste may thus be symbolised:

S
P st P
+
S S
___

[Transcriber's note: The underscores represent a horizontal curly brace
in the original.]

the + indicating the position of the absent labellum.

Cases of this kind are the more interesting from th