ix
contained,—these latter, called in their immature state the ovules, being attached to the adherent margins of the folded leaf (Fig. 6). The vessel thus formed is denominated a carpel; the line of adhesion is termed the ventral suture, that opposite to it, representing the midrib of the leaf, the dorsal suture. In many flowers two or more carpels are united, the edges of each carpel-leaf being curved inwards, forming divisions more or less complete, called dissepiments (Fig. 7). In every case the ovules are attached to the ovary by means of a substance called the placenta, formed partly of a prolongation of the vessels of the leaf, partly of cellular tissue connected with that of the style; by the former they receive their nourishment, while through the latter their fertilization is accomplished. When these placentas all meet in the centre, forming with the dissepiments a perfect division between the carpels, the ovary becomes, of course, two- or many-celled; the united placentas are then said to be central or axile (Fig. 8). When they form by their junction a distinct column in the middle of the cavity, they are styled free and central (Fig. 9); when they appear as mere projections from the sides of the vessel, they are called parietal, as in the Poppy (Fig. 10). The ovules are attached to the placenta by means of a small appendage of that organ, to which the name of funiculus is given.
The ovary is sometimes adherent to the tubular portion of the calyx, so as to appear below the teeth or sepals of the latter; it is then termed inferior, the calyx being superior (Fig. 11). When free in the middle of the flower, it is called superior, the calyx becoming inferior (Fig. 12).
In the Coniferæ or Fir tribe and a few other plants there is no ovary,—the ovules being produced without any covering, in the axils of the modified bracts or leaves which form the cone, or covered only by those leaves converted into a fleshy substance as in the so-called berries of the Juniper and Yew.
In some plants the ovaries and the stamens are contained in
