270 STRUCTURE OF THE CARPEL.—THE STYLE. 
an analogous structure. Thus it consists of parenchyma, which 
is often much developed, and through which the vascular bundles 
composed of spiral and other vessels ramify, and either converge 
towards the base of the style, or terminate at the upper part of 
the ovary when the style is absent. 
Fie. 594. 
% 
A 
A 
z 
A= 
| 
s 
i & 
s 
Fig. 594. Vertical 
section of the 
carpel of the Ap- 
ricot. ov. Ovule, 
which is enclosed 
in an ovary. ep. 
Epidermis, form- 
ing the external 
coat of the ovary. 
me. Middle layer. 
end. Inner coat 
te. Style with a 
canal in its cen- 
The whole is covered ex- 
ternally by a layer of epidermis ( fig. 
594, ep). The parenchyma is usually 
of a more lax nature as we proceed 
towards the inside of the ovary, 
where it forms avery delicate lining, 
end, which is called by Schleiden 
epithelium ; it corresponds to the 
epidermis of the upper surface of 
the blade of the leaf. The epidermis 
on the outside of the ovary corre- 
sponds to that of the lower surface 
of the blade, and like it is frequently 
clothed with stomata, and sometimes 
with hairs. The parenchyma, me, 
between the inner lining of the ovary 
and epidermis, corresponds to the 
general parenchyma of the lamina, 
which is similarly placed. Where the margins of the blade of 
the carpellary leaf meet and unite at the ventral suture (jig. 
586, vs), a layer of parenchymatous tissue is developed, which 
forms a more or less projecting line in the cavity of the ovary, 
called the placenta (fig. 585, p), to which the ovule or ovules 
are attached (fig. 628, pl). This placenta is essentially double, 
the two halves being developed from the two contiguous 
margins of the blade of the carpellary leaf. ? 
The style has been considered by some botanists as a pro- 
longation of the midrib of the blade (fig. 589, p, s), but from 
the arrangement of its tissue it is to be regarded rather as a pro- 
longation of its apex, the margins of which have been rolled 
inwards and united. It consists of a cylindrical process of 
parenchyma, traversed by vascular tissue, which is so arranged 
as to form a sort of sheath at its circumference (fig. 596, ¥, v, v), 
and is a continuation of that of the ovary ; it proceeds upwards 
without branching towards the apex of the style, but always 
terminates below that point. The style is invested by epidermis 
continuous with that of the ovary, and furnished occasionally, 
like it, with stomata and hairs. 
Upon making a transverse (fig. 596), or vertical section (fig. 
594), of the style, we find it is not a solid body as we might 
have supposed, but that it is rarely traversed by a very narrow 
canal (figs. 594 te, and 596, »), which communicates below with 
the cavity of the ovary, and above with the stigma. This canal 
is either always entirely open, or more or less obstructed, as in 
Orchids (fig. 595, can), or far more commonly filled up by a 
tre. st. Stigma. 
