Pistil.
sti, stigma; sty, style; ov, ovule. After Bergen.
The pistil, or the female sexual organ of the flower, usually consists of a small hollow chamber called the ovary, which contains the ovules, and of a slender portion or stalk, called the style. At the top of the latter is found a ridge, knob, or point which is called the stigma.
The stigma consists of cells loosely arranged over the surface. These cells secrete a moist substance, to which the pollen grains adhere when they come in contact with the stigma. Beneath these superficial cells, running down through the style, there are found long cells, with intermediate spaces, through which the pollen tube reaches the ovary.
CUT XL.
Stigma of thorn-apple with pollen.
p, pollen forming into a pollen-tube; i, intermediate space. After Bergen.
The ovules are not borne indiscriminately by any part of the lining of the ovary. They grow in a line running along one side of the ovary, as may be seen in the pea pod. This ovule-bearing line is called the placenta.
The ovule usually exists as a roundish or egg-shaped mass, with a small opening leading into the apex. This opening leads to a sac inside the ovule, which is filled with a soft protoplasmatic material and cells and is known as the embryo sac. Minute cells are found at the apex of the ovule from the development of which the embryo is produced, after the union of the pollen with a cell at the apex of the embryo sac of the ovule has taken place.
CUT XLI.