444 
pith ; though there are some roots which have 
no pith at all ; while there are others which 
have little or none at the extremities, but a 
considerable quantity near the trunk. The 
cuticle, in all roots, at a certain age, is dou- 
ble; the cortical substance, or bark, differs 
greatly in its quantity and disposition in dif- 
ferent plants. 4 he roots, as w T ell as the 
trunk of plants, are furnished with a variety 
of vessels for the purpose of conveying and 
circulating air and the juices necessary to 
their nourishment. 
In hg. 188. is a section of the root of worm- 
wood, as it appear? to the eye; and fig. 
189. is the same magnified. A A, the skin 
with its vessels; BB, the bark; CCC, the 
lymph-ducts of the bark; the other holes 
are small cells or sap-vessels. DDD, pa- 
renchymatous insertions from the bark ; 
EEE, the rays of the wood, with the* air- 
vessels. This root has no pith. 
III. The leaves are organs essential to the 
existence of plants. Trees perish when to- 
tally divested of them ; and in general, when 
stript of any considerable proportion of their 
leaves, they do not shoot vigorously. The 
leaves exhibit a beautiful appearance when 
the intermediate parenchymatous matter is 
consumed by putrefaction. Both surfaces 
ot the leaf are covered with a membrane, 
which is a thin bark, continued from the 
scarf-skin of the stalk. 
IV. The flower consists of four parts, the 
calyx, the corolla, the stamina, and the pis- 
tillum. I he calyx or flower-cup is almost 
always of a green colour, and is that which 
surrounds and supports all the other parts 
of the flower. The corolla is of various co- 
lours, is variously shaped in different vege- 
tables, and is that which constitutes the most 
conspicuous part of the flower. It sometimes 
consists of one continued substance, but more 
frequently of several portions, which are 
called petals. The stamina are supposed to 
be the male part of the flower. Tin use us 
defines them to be an entrail of the plant, 
designed for the preparation of the pollen. 
Each stamen consists of two parts; the fial- 
mentum or fine thread which supports the 
anthera, and the anthera itself, which con- 
tains within it the pollen, and when come to 
maturity bursts and discharges it for the im- 
pregnation of the germen. From the sup- 
posed function of the stamina, they afford 
the chief foundation of the distribution of the 
vegetable system into classes. Such flowers 
as want this part are called female ; such as 
have it, but want the pistilluin, are male; 
such as have them both, hermaphrodite ; and 
such as have neither, neuter. ' 
The pistil! um or pointal is supposed to be 
the female pa. t of the flower; it is defined 
by Linnaeus to be an entrail of the plant, 
designed (or the reception of the pollen. It 
consists of three parts,- the germen, the style, 
and the stigma. The germen is the rudi- 
ment of the fruit accompanying the flower, 
but not yet arrived at maturity. T he style 
is the part which serves to elevate the stigma 
from the germen. The stigma is the sum- 
mit of the pistilluin, and is covered with a 
moisture for the breaking of the pollen. See 
Botany. 
The pericarpium or seed-vessel is the ger- 
men grown ^maturity. Such are the con- 
stituent parts of the flower; they are how- 
PLANTS. 
ever infinitely varied, and serve both to di- 
versify" the face of nature, and to interest and 
delight the curiosity of man. One curious 
tact it is necessary to notice, before we dis- 
miss tins' branch of the subject, and that is, 
that in the perennial plants especially, every 
flower is perfectly formed many months be- 
fore it makes its appearance. Thus the flow- 
ers which appear in this year are not properly 
the productions of this year ; the mezereon 
flowers in January, but the flowers are com- 
pletely formed in the bud in the preceding 
autumn: the same is obvious in the kalmir 
and rhododendron. If the coats of the tulip- 
root also are carefully separated about the 
beginning of September, the nascent flower, 
which is to appear in the following spring, 
will be found in a small cell, formed by the 
innermost coats, as represented in plate fig. 
190, where the young flower A appears to- 
wards the bottom of the root. 
V. 'I he fruit consists of nearly 7 the same 
parts as are found in the stem ; of a skin or 
cuticle, which is a production or continuation 
of the skin of the bark ; and of an outer paren- 
chyma, which is the same substance conti- 
nued trom the bark, only that its vesicles are 
larger and more succulent or juicy. Next 
the core there :s commonly an inner pulp or 
parenchyma; and the core is no more than 
a hard woody membrane, which incloses the 
seed. It is to be observed, however, that 
the organization of fruit is very various; in 
some the seeds are dispersed through the 
parenchymatous or pulpy substance; in 
some, instead of a core, we find a strong 
woody substance, inclosing the seed or ker- 
nel, which from its great hardness is termed 
the stone; in some, there are a number of 
seeds ; and in others, only a single seed, in- 
closed in a large mass of parenchymatous 
matter. 
VI. The seed is a deciduous part of a ve- 
getable, containing the rudiment of a new 
one. The essence of the seed consists in the 
corculum or little heart, which is fastened to 
the cotvledones or lobes, and involved in 
them, and closely covered by its proper 
tunic. The corculum consists in the plu- 
mular, which is the vital speck of the future 
plant, extremely small in its dimensions, but 
increasing like a bud to infinity. The ros- 
telluin, however, must be included, which is 
the base of the plumula; it descends and 
strikes root, and is the part of the seed ori- 
ginally contiguous to the mother-plant. It 
is commonly supposed, and with some reason, 
that the perfect plant, or at least all the or- 
ganization which is requisite to a perfect plant, 
exists in the seed surrounded by a quantity 
of farinaceous matter, which serves to ab- 
sorb moisture, and to furnish nourishment to 
the corculum till its parts are sufficiently un- 
folded to draw support from the soil. A kid- 
ney-bean, or lupin, when it has been soaked 
for some time in water, and begun to swell, 
is easily se >a rated into its two lobes; and 
between these is displayed the nascent plant. 
I he naked eye can easily discern the stem, 
and its connection with the lobes. Through 
the lobes are diffused innumerable vessels, 
which immediately co mmunicate with the 
embryo plant. On the external surface of 
the seed are absorbent vessels, which attract 
the moisture; by this moisture a degree of 
fermentation is produced; and thus a juice 
is prepared by a natural process, in every 
respect proper for the nourishment of the 
plant in its first efforts to extend its tender 
frame. The plant in its infancy is almost a 
gelatinous substance, and increases and indu- 
rates by degrees : and in general the hardness 
oi wood bears a pretty exact proportion to 
the slowness with which a plant increases. 
1 hat part of the stem which is next the root 
is the first which assumes the woody texture. 
M. Bonnet, in order to ascertain how far 
the lobes of the seed were necessary to the 
growth and health of the corculum, detached 
them with great dexterity without a vital 
injury to the infant plant. Some French 
beans treated in this manner, and sowed in 
a light soil, grew ; but the consequence was, 
that not only the first leaves were much 
smaller, but the plants were uniformly weaker 
in every part of their growth than others, 
which tor the sake of comparison were sown 
at the same time without being mutilated. 
'Fhe plants from the seeds which were de- 
pi i\ ed oi the lobes put forth tewer blossoms, 
and produced less seed. The seeds of 
mosses are naturally devoid of lobes. The 
first leaves which make their apppearance, 
and which are called seminal, appear not 
less necessary to the perfection of the plant 
than the farinaceous lobes. If they happen 
to be broken off, the plant experiences a 
proportional loss of vigour. 
It is matter of curious observation, that 
seed, thrown into the ground at random, 
should always come up in the proper direc- 
tion. M. Dodart has offered an ingenious 
explanation of this fact, which consists in 
supposing that the rostellum contracts- by 
humidity, and that the plumula on the con- 
trary contracts by dryness. According to 
this idea, when a seed 'is put into the ground 
the wrong way, the rostellum, which then 
points upwards, contracts itself towards t he 
part where there is most humidity, and there- 
fore turns downwards. The plumula on the 
contrary pointing downwards, turns itself to- 
wards the part of the soil which is driest, and 
therefore rises towards the surface. Yhis 
explanation, however, evidently rests on no 
better basis than conjecture; the experiments 
in which the truly philosophical Mr. Knight 
is now engaged, will probably decide the 
question. 
Independant of the seed, there are two 
other methods by which plants are propa- 
gated, by slips and suckers; and many plants 
naturally make an effort to propagate them- 
selves in this manner. The bulbous-rooted 
plants in general increase by offsets. When 
a tulip is first planted in the spring, the stem 
issues from the inner part of the bulbous 
root; but when the tulip is taken up in the 
autumn, the stem no longer pioceeds from 
that part of the root, but seems attached to 
one side. The fact is, that the root which is 
taken up is only a part of that which was 
planted. .Some of thp outer layers of the 
original root have decayed, by having the sub- 
stance absorbed for the nourishment of the 
blossom, and from the remainder what may 
be termed a new root has been provided for 
the future year. 
Besides the parts above-mentioned, some 
writers have treated of the nerves and muscles 
of vegetables. These, it is confessed, have 
never been demonstrated, but their existence 
has been inferred from the motions of peculiar 
parts of vegetables, and more particularly 
