30 
INTRODUCTION TO BOTANY. 
tinct, usually of a green colour, and of a ruder 
and less delicate texture than the corolla. 
Authors have long disputed ahout the defi- 
nition of a calyx, and the limits which really 
exist between it and the corolla ; the above, 
which is copied from Link, seems to be the 
only one that can be considered accurate. 
In reality, in many cases, they pass so in- 
sensibly into each other, as in Calycanthus and 
Nymphaea, that no one can say where the 
calyx ends, and the corolla begins, although 
it is evident that both are present. Linnaeus, 
indeed, thought that it was possible to distin- 
guish them by their position with regard to 
the stamens, asserting that the divisions of 
the calyx are opposite those organs, and 
of the corolla alternate with them ; but if this 
distinction were admitted, the corolla of the 
primrose would be an inner calyx, which is 
manifestly an absurdity. Jussieu defines a 
calyx by its being continuous with the pe- 
duncle, which the corolla never is,but there are 
plenty of true calyxes, of all papaveraceous 
and cruciferous plants for instance, in which 
the calyx is deciduous, and not more con- 
tinuous with the peduncle than the corolla 
itself. The only just mode of distinguishing 
the calyx, seems to me to be, to consider it in 
all cases the external verticillate series of the 
integuments of the flower, within the bracts, 
whether it be half coloured, deciduous, and of 
many pieces, as in Crucifers ; membranous 
and wholly coloured as in Mirabilis ; green 
and campanulate or tubular as in Laurus and 
Ly thrum. Upon this principle, wherever there 
is only one series of floral integuments, 
that series is the calyx. A calyx, therefore, 
can exist without a corolla ; but a corolla 
cannot exist without a calyx, either perfect or 
rudimentary. The term perianth is sometimes 
given as synonymous with calyx ; but this 
is an error. The word perianth signifies 
the calyx and corolla combined, and is there- 
fore strictly a collective term. It should only 
be employed to designate a calyx and corolla 
the limits of which are undefined, so that they 
cannot be satisfactorily distinguished from 
each other, as in most monocotyledonous plants / 
the tulip and orchis for example." — P. 327. 
" That envelope of the flower which forms 
a second whorl within the calyx, and between 
it and the stamens, is called the corolla. Its 
divisions always, without exception, alternate 
with those of the calyx, and are called petals. 
Like sepals, (the divisions of the calyx,) they 
are either united by their margins, or distinct ; 
but unlike the calyx, they are rarely green, 
being for the most part either white, or of 
some colour such as red, blue, or yellow, or of 
any of the hues produced by their intermix- 
ture. The corolla is generally also larger 
than the calyx. * * * When the petals of 
a corolla arc all distinct, then the corolla is 
said to be polypetalous, but if they cohere at 
all by their contiguous margins, so as to form 
a tube, it then becomes what is called mono- 
petalous. * * * A petal consists of the 
following parts ; — the limb or lamina, and the 
unguis or claw. The claw is the narrow part 
at the base, which takes the place of the foot- 
stalk of the leaf, of which it is a modification ; 
the limb is the dilated part supported upon 
the claw, and is a modification of the blade of 
a leaf. In many petals there is no claw, 
as in Rosa ; in many it is very long, as in 
Dianthus."— Pp. 330, 333, 334. 
" Next the petals in the inside are seated 
the organs called stamens — the apices of old 
botanists. These constitute the androeeeum 
or male apparatus of the flower, like the calyx 
and corolla are modifications of leaves, and 
consist of the filament, the anther, and the 
pollen, of which the two latter are essential : 
the first is not essential ; that is to say, a 
stamen may exist without a filament, but it 
cannot exist without an anther and pollen. All 
bodies therefore which resemble stamens, or 
which occupy their place, but which are desti- 
tute of anthers, are either petals or appendages 
of the petals, or abortive stamens." — P. 338. 
" The last organ to enumerate in the 
flower is that which constitutes the female 
system, or gynaaceum of Roper, and which is 
usually called the pistil. In all cases it occu- 
pies the centre of the flower, terminating the 
axis of growth of the peduncle ; and is conse- 
quently the part around which every other 
organ, without exception, is arranged in her- 
maphrodite structures. It is distinguished 
into three parts, the ovary, the style, and the 
stigma. The ovary, called germen by Lin- 
naeus, is a hollow case placed at the base of 
the pistil, enclosing the ovules, and always 
containing one or more cells or cavities. It 
is the part which ultimately becomes the fruit. 
* * * The style is that elongation of the 
ovary which supports the stigma. It is 
frequently absent, and then the stigma is 
sessile ; it is not more essential to a pistil, 
than a stalk to a leaf, or the claw to a petal, 
or the filament to a stamen. * * * Xhe 
stigma is the upper extremity of the style, 
without epidermis ; in consequence of which 
it has, almost uniformly, either a humid or 
papillose surface."— Pp. 363, 364, 367. 
We must pass by, with mere mention, much 
that is interesting in reference to the fruit 
and seed, and also a critical and somewhat 
lengthy account of the compound organs of 
flowerless plants, in order to make room for 
the following admirable sketch of a plant in 
a state of vital action. The author frequently 
presses the recognition of the " vital power," 
