386 BOTANY AS APPLIED TO VETERINARY SCIENCE. 
female organs, they are situated on separate flowers, while in 
others they exist only on different plants. 
The calyx, or flower-cup (fig.2, a), is the external envelope of 
the flower, surrounding the co¬ 
rolla. It consists of two or 
more divisions, called sepals, 
which are either distinct, when 
it is called polysepalous, or which 
are united at their margins, and 
then called monosepalous. It is 
generally green in colour, but in 
some flowers, as the fuschia, &c., 
it is highly coloured. It varies 
much in shape, and like all the 
other appendages of the flower 
is a modification of the leaf. 
Its use is to protect the bud before it expands. 
The corolla (fig. 2, b b) is situated within the calyx, and con¬ 
sists of either a single piece or petal, when it is called 
monopetalous, or is divided into several, when it is called 
polypetalous. It has generally a more delicate texture than 
the calyx, and gives the brilliant colours and fragrance for 
which most flowers are so much admired. In some plants it 
is absent, in others it constitutes the only envelope. It is 
generally divided into two parts, the lower, called the claw, 
and the upper expanded portion, the limb, the former 
corresponding to the stalk, the latter to the laminae of the 
leaf. It varies much in shape and outline, sometimes giving 
distinct characters to orders, as in the lip-shaped corolla of 
the Natural order Labiates, the cruciform in the Natural order 
Crucifera. 
Fig. 3. The stamen (fig. 3, a a) is situated 
within the corolla, and constitutes 
the male organ of the plant. It 
usually consists of two parts, viz., 
filament (fig. 3, a a) and anther (fig. 
3, b). 
The filaments are either distinct 
or united by their margins. If into 
one tube, they are called monadel- 
phous ; if in two parts, diadel- 
phous; and if in several, polyadel¬ 
phous. The filament is not essential 
to the stamen. When absent it 
is said to be sessile. Attached to the summit of the filament 
we have the anther, which is formed in most instances of two 
Eig. 2. 
