VI
They are generally unequal, the two lateral pieces corresponding in
form and size, while that between them, called the lip, is of some other
form and size; in the genus Thelymitra, however, and in Paxtonia, they
are all alike. Nothing can be more variable than the proportions they
bear to each other and to the exterior pieces. It is only a few of their
modifications which it seems important to notice. The lateral pieces
are occasionally bifid, as in certain species of Habenaria ; in Megaclinium
falcatum they are glandular at the apex ; in most cases they are
distinct from the column, but in Lepanthes, Gongora, Disa, and some
others, they are adnate to that organ ; in no instance are they spnrred
or saccate. The lip is either distinct from the column or united to it,
stalked at its base or dilated there, and often extended into a bag or
spur, which is sometimes, as in certain species of the genus Epidendrum,
consolidated with the ovary; very rarely it has two spurs, as in Diplocentrum.
In the instances of Camarotis and Acropera it is saccate at the
point. Its form is infinitely varied, the extremes of variation being
Paxtonia for simplicity, and Coryanthes or Stanliopea for complexity;
these and all other complicated forms may without difficulty be reduced
to a three-lobed type, the simple form of which is found in Maxillaria,
Bletia, and many Cattleyas. The lip is often so slightly articulated with
the column as to swing to and fro upon the least disturbance, on which
account it sometimes seems as if it were endowed with a power of spontaneous
motion ; this is particularly apparent in certain species of Pterostylis.
There is a frequent tendency in the lip to produce tubercles or
lamellse upon its surface, the latter are always confined to the veins, the
former are principally found near the base of the lip, and do not appear
to have any relation to the veins ; it is in the genus Oncidium, Eria, and
Zygopetalum that these bodies, the use of which is unknown, are most
conspicuous. Not unfrequently the lip is hairy, convex, and so marked
and coloured as to bear no little resemblance to an insect.
It is usual to call the exterior series of the floral envelopes, calyx, and
the interior, corolla, and it is convenient so to consider them for purposes
of description. It is however probable, both from the analogy of Marantaceee
and Zingiberace®, and for other reasons, that the so called sepals
are really the petals, and that the so called petals are an outer row of
sterile stamens. It is clear that the supposed calyx is not the most
vii
exterior of the floral envelopes, not only because in Epistephium there is
an obscurely three-lobed cup still more external, but especially because
in Bolbophyllum bracteolatum there are two scales or rudimentary sepals
alternate with the so called sepals on the outside. That the supposed
petals are sterile stamens is rendered probable, 1°. by the general tendency
of one of them to become three-lobed, in which case the middle
lobe may be regarded as equivalent to the connective, and the lateral
lobes to the cells of the anther; 2°. by the glandular termination of
these parts in Megaclinium falcatum and elsewhere, a common sign
among other plants of the suppression of an anther, and thirdly because
they have all been seen transformed into stamens by His and Brown. It
is however remarkable, that the last-mentioned botanist does not consider
such monstrous cases as good evidence of the so called petals being
modified stamens, and that he regards the additional part in Epistephium
to be analogous to what is termed a calyculus in some Santalaceee, a few
Proteacece, and perhaps Loranthaceae. It might however be argued
that the so called calyx of those orders is really corolla.
The centre of the flower is occupied by a body called the COLUMN,
which is formed by the consolidation of the style and true stamens. In
the greater part of the order there is but one stamen present, and it is
in that case placed opposite the intermediate sepal, and consequently
alternate with the lateral petals; when, as in Cypripedium there are two
stamens present, then the usual stamen remains in its customary position,
in a sterile state, and the two perfect stamens are additional and
placed right and left of it. It is supposed that in those species which
have but one anther there are two other stamens present in an incomplete
condition, and consolidated with the other ; and from the evidence
offered by monstrous formations, it is thought that such sterile stamens
are represented in Orchis and its allies by two tubercles, one on each
side of the column, in Burlingtonia by two auricles near the apex of the
column, and by other signs in other cases. This theory is in some
degree confirmed by the genus Zygostates, in which what appear to be
the sterile stamens are present in a perfectly distinct state, while there
are no lateral appendages of any kind upon the column. But on the
other hand it is invalidated by a monster of Platanthera bifolia,
described by Dr. Brown, in which three stamens were developed, each