EXPLANATION OP PLATES.
VOL. V.—PART I.
ORCHIDEJ2.
This very interesting order of monocotyledonous
plants is, deservedly, a universal favourite with both
cultivators and Botanists. With the former on account
of the numerous flowers of surpassing beauty
which it provides, and with the latter, on account
of the endless variations of form and combination
which its few and simple elementary parts furnish
for his consideration and study. To master these,
however, is a work demanding both time and patience
on the part of the inquirer. ’
Being well aware of this, as well as J if the interest
which attaches to this order I have been induced,
at the risk of falling into many blunders, to devote an
unusully large space of this work to its elucidation
even at this late stage of my progress (the present
being the concluding volume) while so many others
of great interest and difficulty still remain untouched.
Reduced to its elements, the flower of an Orchid
(I use the term collectively of the whole order) is
sufficiently simple, consisting of a perianth (the floral
leaves) of six parts; one, rarely two, and still more
rarely, three fertile stamens: a stigma: and an ovary.
The perianth is disposed in a double series, the three
exterior parts being equivalent to the calyx (sepals)
the three interior to the corolla (petals) one of which
from differing more or less in form colour and
texture from the other two has, from being usually
placed in front and in the most dependent part of
the flower, received the name of the Lip. This last
with its appendage, the spur, is the most important
piece of the six forming the perianth, from its generally
furnishing marks, often of great value, in the
discrimination of genera, which the others seldom
do. Were the flower complete in all its parts, it
would have three perfect stamens, in place of which,
it has usually only one, and that so masked that
persons who have not studied the family scarcely
know how or where to look for it. It is in the centre
of the flower forming part of the thick, more or less
elongated body called the column, having its anther,
or polleniferous portion, resembling, in many cases,
a little cap containing the pollen lying on the top.
On the side of the column next the lip, if attentively
looked for, will be seen a slight moist somewhat
glistening glutinous depression; that is the
stigma. The stamens and pistil are therefore combined
to form the column. In Satyrium this structure
is somewhat departed from, the stigma being
terminal and two-lobed, and the cells of the anther
quite distinct.
The pollen is very variable and, to the Botanist,
is the most important part of the organization, as we
shall by and bye see.
These few elementary parts vary so much among
themselves in form, position, and combination, as to
have enabled Botanists, in the course of their researches,
to construct from them about 400 genera,
for the accommodation and more easy discrimination
of probably not fewer than between three and
four thousand species. Amidst so great a number
of variations, it is almost impossible for words to convey
to the mind an adequate conception of the innumerable
minute points of difference which mark the
narrow boundaries between so great a number of
gene ra; the aid therefore of the pencil becomes
nearly indispensable. Under this conviction I have
deemed it advisable to give analyses of as many
genera as I could, and have fortunately been able
to produce representations of upwards of 70, a great
number certainly when it is considered that Wal-
lich’s list of Indian plants includes only 63 genera.
I have still in my possession, drawings of several
others, but not the specimens from which to complete
their generic analysis. This statement is not
made in the spirit of boasting, far from it, but simply
to show that though much as has already been done,
towards acquiring a knowledge of Indian Orchideae,
much still remains to be done and thereby encourage
our successors to persevere, having the assurance
.of still finding a rich harvest of novelties, to reward
their diligence.
To assist those who may not have studied the
floral structure of the order, or who may not have
the means of consulting books, descriptive of its
Organization, I shall here give a very brief account
of it, merely sufficient to enable any one to understand
the following dissections.
To prevent misunderstanding, it is necessary to
premise that I view the flower in the position it
usually presents itself when looked at in front, that
is, with the lip next the beholder and more or less
dependent. On looking at the flower from behind,
it is the most remote anterior portion. The lip being
anterior, the odd sepal and pair of petals are posterior,
or next the axis or stalk. Such is the usual position,
but sometimes it is reversed and the lip is at the top
of the flower, and then is next the stalk, or posterior,
as in Polystachya and Satyrium (the lip forms the hood
or galia of the last) the flower is then said to be rtsu-
pinate, though that in truth is the normal position
of the flower. The usual position is produced by
the ovary receiving a half twist which brings the
lip from the upper to the lower sid e: or in other
words places it in the front (anterior) in place of the
back of the flower. How this change is brought
about it is not always easy to say, but we may for
convenience assume that it is often the result of
gravitation, for being the bulkier and heavier part,
it has a natural tendency to seek the lowest side
and in doing so twists the young and pliable ovary.
Beginning from without w e find three sepals, these
are either all distinct and equal, or the two anterior
ones are large or small, divided or entire, are spreading
or appressed to the lip, are more or less united
either directly to each other or through the medium of
the prolonged base of the column, in the latter case
forming a spurious spur or in those cases where the
columnar process is broad what is called a mentum or
chin—many of the Dendrobrums afford examples of
the former and Certopera fusca of the latter. Some-
A
H i )