258 
RUDIMENTS OF THE NATURAL SYSTEM OF BOTANY. 
Examples have been given in which the three positions of upright, pendulous, and 
horizontal, or parallel with the placenta, are discernible in as many species of the 
same genus. Yet these do not destroy the validity of the character in other Orders. 
They only demonstrate the necessity for embracing every point of distinction, and 
not depending on isolated marks. 
Every ovule, whatever be its shape, will, when attentively examined, be found 
to have a small aperture on some part of its surface. Botanists designate this little 
cavity the foramen ; and the course it takes outwards, or the direction in which the 
orijSce points, is looked upon as the line in which the future radicle or first root will 
protrude itself. The latter test is of great moment to the scrutinising observer ; 
for there are Orders which derive much of their distinctiveness from having the 
radicle directed in a contrary course to that usually taken. In general, the radicle 
points to the hilum or umbilicus, which is the little stalk that attaches the ovules 
to the pericarp or its placentae. 
When the ovarium is fully ripened, it assumes the name of fruit. The shape 
and texture of this organ are exceedingly diversified, and give rise to many 
designatory appellations. A fruit is always composed of two separate parts, which 
are known as the pericarp and the seed. With the first of these alone we have 
now to deal. The pericarp is commonly divided into the epicarp, or the exterior 
rind or shell, which is popularly recognized as the husk of Horse or Spanish 
Chestnuts, &c. ; the sarcocarp, or fleshy portion, as the edible part of the apple, 
plum, or peach ; and the endocarp, or interior coat or shell, which may be illus- 
trated by the stones of cherries, &c. It frequently happens that one or two of the 
above are not to be discovered ; and it has been long believed that some fruits have 
no pericarpial covering, but are simply naked seeds. The plants belonging to the 
second Order of the fourteenth Class in Linnasus's arrangement, and the Order 
Lahiaice of the Natural System, have thus been deemed to have their individual 
seeds exposed. Later botanists have proved this to be a complete fallacy, resulting 
from imperfect investigation ; each of the little seeds in LahiatcE having a manifest 
pericarp, independently of the seminal integument. Truly naked seeds are, never- 
theless, observable in a few Orders, and are considered very remarkable. 
The divisions of the pericarp, like those of the ovary, are of first-rate importance 
to the student. Having formerly remarked on these, we shall only further notice 
that when the pericarp is separated externally into a number of lesser cases or 
cavities, each bearing a separate style and stigma, and containing one or more seeds, 
such minor vessels are denominated carpels. On the dehiscence or indehiscence of the 
pericarp, or its power or incapacity for splitting when mature, and either ejecting 
the seeds or sufi'ering them to drop out, very serviceable distinctions are likewise 
founded. 
Analogous to the ripened ovary being called the fruit, is the designation of seed, 
which is applied to the ovule after it has reached its natural size. The hints that 
have been thrown out with regard to the position of the ovules, hold good in 
