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Updated: May 10, 2025
They are rudiments hints that the nut ought to have, perhaps had uncounted ages since, not one ovule, but three, the type-number in palms. One ovule alone is left; and that is opposite the one eye which is less blind than the rest; the eye which a schoolboy feels for with his knife, when he wants to get out the milk.
Sexual reproduction is quite a distinct matter. Here, in all these cases, what is required is the detachment of two portions of the parental organisms, which portions we know as the egg and the spermatozoon. In plants it is the ovule and the pollen-grain, as in the flowering plants, or the ovule and the antherozooid, as in the flowerless.
The result of this act on the part of the male and female is, that the formation of a new being is set up in the ovule or egg; this ovule or egg soon begins to be divided and subdivided, and to be fashioned into various complex organisms, and eventually to develop into the form of one of its parents, as I explained in the first lecture.
Even in first crosses, the greater or lesser difficulty in effecting a union apparently depends on several distinct causes. There must sometimes be a physical impossibility in the male element reaching the ovule, as would be the case with a plant having a pistil too long for the pollen-tubes to reach the ovarium.
The result of this act on the part of the male and female is, that the formation of a new being is set up in the ovule or egg; this ovule or egg soon begins to be divided and subdivided, and to be fashioned into various complex organs, and eventually to develop into the form of one of its parents, as I explained in the first lecture.
In certain whole groups of plants the ovules stand erect, and in others they are suspended; and within the same ovarium of some few plants, one ovule holds the former and a second ovule the latter position. These positions seem at first purely morphological, or of no physiological signification; but Dr.
If you search among the cream-layer at the larger end of the nut, you will find, gradually separating itself from the mass, a little white lump, like the stalk of a very young mushroom. That is the ovule. In that lies the life, the 'forma formativa, of the future tree. How that life works, according to its kind, who can tell?
In Casuarina, Juglans and the order Corylaceae, the pollen-tube does not enter by means of the micropyle, but passing down the ovary wall and through the placenta, enters at the chalazal end of the ovule. Such a method of entrance is styled chalazogamic, in contrast to the porogamic or ordinary method of approach by means of the micropyle. Embryology.
Careful examination further proves that the whole substance of the nettle is made up of a repetition of such masses of nucleated protoplasm, each contained in a wooden case, which is modified in form, sometimes into a woody fibre, sometimes into a duct or spiral vessel, sometimes into a pollen grain, or an ovule.
They are in every female at birth, and as the girl develops into womanhood, these ovules develop also. At a certain age, varying slightly with the individual, the ripest ovule leaves the nest or ovary and comes down one of the tubes connecting with the womb and passes out of the body. When this takes place, it is said that the girl is at the age of puberty.
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