. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. FLOWERS 33 wise; notice that the style appears to be composed of rather spongy material m the interior; the ovary is hollow and is seen to contain a num- ber of rounded structures which appear to grow out from the wall of the ovary. These are the ovules. The compartments in which they grow are called the locules. How many locules do you find in a cross section of the lily ? ^ That part of the ovary wall from which the ovules are outgrowths is called the placenta (plu. placentcB). How many p
. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. FLOWERS 33 wise; notice that the style appears to be composed of rather spongy material m the interior; the ovary is hollow and is seen to contain a num- ber of rounded structures which appear to grow out from the wall of the ovary. These are the ovules. The compartments in which they grow are called the locules. How many locules do you find in a cross section of the lily ? ^ That part of the ovary wall from which the ovules are outgrowths is called the placenta (plu. placentcB). How many pla- centae do you find, and how would you locate them with reference to the outside of the ovary ? Fertilization of the Flower. — The ovules, under certain conditions, become seeds. An expla- nation of these condi- tions may be had if we examine, under the mi- croscope, a very thin section of a pistil, on which pollen has begun to germinate. The cen- tral part of the style is found to be either hollow or composed of a soft tissue through which the pollen tube can easily grow. Upon germina- tion, the pollen tube grows downward through the spongy center of the style, follows the path of least resistance to the locule of the ovary, and there grows into the ovule. It is believed that some ^ The structural differences in the flower of a monocotyledon and dicotyledon may well be pointed out here. hunter's BIOL. — 3. Fertilization of the ovule. The pollen tubes pass through the stigma and style, finally entering the cavity (locules) of the Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Hunter, George William, 1873-1948. New York, American book company
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