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_INTRODUCTION._
1. VEGETABLES or PLANTS are natural bodies endowed with organization and
life, but destitute of voluntary motion and sense; and BOTANY is that
branch of natural science which treats of their structure and functions,
the systematical arrangement and denomination of their several kinds, and
their peculiar properties and uses.
2. The principal parts of plants are the _root_; the _herb_ or plant
itself; and the _fructification_, or flower and fruit.
3. As it is the sole object of this introduction to describe, in a concise
manner, the Linnæan arrangement of plants, for the purpose of explaining
the classification adopted in the present volume, the parts of
_fructification_ only will be mentioned. These are the calyx, corolla,
stamens, pistil, seed-vessel, seeds, and receptacle.
4. The CALYX, or flower cup, is the green part which is situated
immediately beneath the blossom. In some plants this consists of one, in
others of several leaves; and it is frequently tubular, as in the
polyanthus, and cowslip.
5. The COROLLA, or blossom, is that coloured part of every flower on which
its beauty principally depends. The leaves that compose it are denominated
_petals_. Some flowers, as the convolvolus and campanula, have only a
single petal; and others, as the rose and peony, have several petals.
6. In the centre of the flower there are two kinds of organs on which the
fructification and re-production of the species more particularly depend.
These are the stamens, and the pistil. The STAMENS are slender,
thread-like, substances, which surround the pistil. They each consist of a
_filament_ or thread, and an _anther_ or summit: the latter contains, when
ripe, a fine dust or powder called _pollen_. This, though, to the naked
eye, it appears a fine powder, is so curiously formed, and is so various in
different plants, as to be an interesting object for the microscope. Each
grain of it is, commonly, a membranous bag, round or angular, rough or
smooth, which remains entire till it meets with any moisture; it then
bursts and discharges a most subtile vapour.
7. The PISTIL is a prominent part, immediately in the centre of each
flower, which adheres to the fruit, and is destined for the reception of
the pollen. Some flowers have only one pistil; others have two, three,
four, &c. and others more than can be easily counted.
8. At the foot of the pistil is situated the _germen_. This, when grown to
maturity, has the name of pericarp or SEED-VESSEL, and is that part of the
fructification which contains the seeds: whether it be a _capsule_ as in
the poppy, a _nut_ as the filbert, a _drupe_ as the plum, a _berry_ as the
gooseberry, a _pome_ as the apple, a _pod_ as in the pea, or a _cone_ as of
the fir-tree.
9. That part of every vegetable, which, at a certain state of maturity, is
separated from it, and contains the rudiments of a new plant, is called the
SEED.
10. The RECEPTACLE is the base which connects all the parts of
fructification together, and on which they are seated. In some plants this
is very conspicuous; and in none more so than the artichoke, of which it
forms the eatable part, called the bottom.
11. The Linnæan system of classification of plants is founded upon a
supposition that the stamens represent the _male_, and the pistils the
_female_ parts of fructification. The whole vegetable creation has been
distributed, by Linnæus, into twenty-four _classes_. These are divided into
_orders_, which are subdivided into _genera_ or tribes; and these genera
are further divided into _species_ or individuals.
12. Of the CLASSES the discriminating characters are taken from the number,
connexion, length, or situation of the stamens. In each of the first twenty
classes there are stamens and pistils in the same flower; in the
twenty-first class, the stamens and pistils are in distinct flowers on the
same plant; in the twenty-second, in distinct flowers on different plants;
in the twenty-third, in the same flower and also in distinct flowers; and
in the twenty-fourth class they are not at all discernible. Thus:
The stamens considered according to their:
_Classes._
{One 1. Monandria.
CLASSES. {Two 2. Diandria.
{Three 3. Triandria.
{Four 4. Tetrandria.
{Five 5. Pentandria.
{Number {Number only {Six 6. Hexandria.
{ { {Seven 7. Heptandria.
{ { {Eight 8. Octandria.
{ { {Nine 9. Enneandria.
{ { {Ten 10. Decandria.
{ { {About twelve 11. Dodecandria.
{ {
{ {and their {Insertion {On the calyx: more than
{ { { nineteen 12. Icosandria.
{ { {Not on the calyx: more
{ { { than nineteen 13. Polyandria.
{ {
{ {Proportion {Four: two long andtwo
{ { unequal { short 14. Didynamia.
{ {Six: four long andtwo
{ { short 15. Tetradynamia.
{
{Connexion by {Filaments {In one set 16. Monadelphia.
{ { united {In two sets 17. Diadelphia.
{ { {In three or more sets 18. Polyadelphia.
{ {Anthers united 19. Syngenesia.
{ {Stamens upon the pistil 20. Gynandria.
{
{Separation of {On the same plant 21. Monoecia.
{ Pistils {On two plants 22. Dioecia.
{ {With flowers of both sexes 23. Polygamia.
{
{Not being discernible 24. Cryptogamia.
13. The characters of the ORDERS are most commonly taken from the number of
the pistils; but sometimes from circumstances relative to the stamens,
pistils, or seed. Those of the _first thirteen classes_ are taken from the
number of pistils, thus:
Monogynia 1 pistil.
Digynia 2 pistils.
Trigynia 3 pistils.
Tetragynia 4 pistils.
Pentagynia 5 pistils.
Hexagynia 6 pistils.
Heptagynia 7 pistils.
Octagynia 8 pistils.
Enneagynia 9 pistils.
Decagynia 10 pistils.
Dodecagynia about 12 pistils.
Polygynia many pistils.
The orders of the fourteenth class, _Didynamia_, are taken from the
situation of the seeds; and are
Gymnospermia naked seeds.
Angiospermia seeds in a capsule.
The orders of the fifteenth class, _Tetradynamia_, are formed from a
difference in the shape of the seed-vessel:
Siliculosa a broad pod.
Siliquosa a long pod.
In the classes _Monadelphia_, _Diadelphia_, _Polyadelphia_, and
_Gynandria_, the orders are taken from the number of stamens:
Pentandria 5 stamens.
Hexandria, &c. 6 stamens, &c.
In the nineteenth class, _Syngenesia_, the orders are taken from the
structure of the flower:
Polygamia æqualis,--all the florets alike.
Polygamia superflua,--the florets of the centre perfect or united; those
of the margin with pistils only, but all producing perfect seeds.
Polygamia frustranea,--the florets of the centre perfect or united; those
of the margin, in general, without either stamens or pistils.
Polygamia necessaria,--the florets of the centre with stamens only; those
of the margin with pistils only.
The classes _Monoecia_ and _Dicoecia_ take their orders from the number and
other peculiarities of the stamens:
Monandria 1 stamen.
Diandria, &c. 2 stamens, &c.
Polyandria 7 stamens.
Monadelphia stamens united into one set.
Polyadelphia stamens united into several sets.
Gynandria stamens upon the pistil.
In the class _Polygamia_ there are three orders:
Monoecia. Dioecia. Trioecia.
The twenty-fourth class, _Cryptogamia_, has five orders:
1. Ferns.
2. Mosses.
3. Liverworts.
4. Flags.
5. Mushrooms.
The Linnæan system is professedly artificial. Its sole aim (observes Sir J.
E. Smith) is to help any one to learn the name and history of an unknown
plant in the most easy and certain manner. This is done by first
determining its class and order; after which its genus is to be made out,
by comparing the parts of fructification with all the generic characters of
that order; and, finally, its species, by examining all the specific
definitions of the genus.
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