Ovule

“ The stalk of an ovule, considerably reduced in normal flowers and much larger in some abnormal flowers, is homologous with a leaf-stalk, with which it agrees in the structure and number of vascular bundles. The facts on which this description is based are derived partly from anatomical evidence, and in part from an account given by a Japanese botanist, Fujii, of several abnormal female flowers; in some cases the collar at the base of an ovule, often described as an arillus, is found to pass gradually into the lamina of a leaf bearing marginal ovules (fig. 14, B) . ”

“ Fig. 249.—Various forms of ovules: A an erect ovule (orthotropous) ; B reversed (anatropous) ; C curved (campylotropous) : k the nucellus (shaded in all the figures) ; s the embryo-sac; ch the base of the ovule (chalaza) ; y and i the external and internal integuments, the dotted line denotes the place where the scar (hilum) will form when the seed is detached from the funicle.
In shape the integuments resemble very closely the cupular [243] indusium of the Hymenophyllaceæ, certain Cyatheaceæ (Fig. 212 E) , and Salvinia (Fig. 218) ”

“ The adnate portion of the funiculus, which appears as a ridge or cord extending from the hilum to the chalaza, and which distinguishes this kind of ovule, is called the Rhaphe. The amphitropous ovule (Fig. 346) has a short or incomplete rhaphe.
322. Fig. 348-352 show the stages through which an ovule becomes anatropous in the course of its growth. The annexed two figures are sections of such an ovule at maturity; and Fig. 355 is Fig. 353 enlarged, with the parts lettered.
Section XII. MODIFICATIONS OF THE RECEPTACLE.
Fig. ”

“ In every woman's ovaries are imbedded millions of ovules or eggs. 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. When it reaches the womb the ovule is ready for the process of conception—that is, fertilization by the male sperm. ”

“ The busy little hose-pipe pushes its way into a little opening at the end of one of the ovules, pumps away till the pollen grain is empty, and the liquid out of it is all safely stored in the ovule, and then it withers away. The ovule when it is ripe is a seed, but if the pollen has not emptied itself in the way just described, the ovule dies.
If you look at Fig. 4 you will see the pistil of a pansy, or heart's-ease. No. 1 is a side view of the pistil sliced down so you can see into it, as you can into a baby-house. ”

“ THE PHYSIOLOGY OF FŒTAL LIFE. The ovule, after it arrives in the uterine cavity, comes in contact at all points with the mucous membrane of the uterus. Its nutrition at first is organic by superficial imbibition; afterwards, probably the villi of the chorion imbibe the fluids there secreted, and transmit them into the space between the chorion and the amnion, thence it transcends through the walls of the amnion, and a portion is conveyed into the fœtus through the umbilical vesicle. ”

“ While the pollen-tube is descending the style, the ovules have arisen as minute cellular outgrowths from the angles of the three chambers of the ovary (Fig. 34, d) . There are two in each chamber. Each ovule is at first a mere solid lump of cells (nucellus) , which curves and becomes enveloped in two thin investing layers, called integuments, as shown in the figures A-D (in Fig. 35) . Inside the solid nucellus, n, of the ovule there soon arises a small cavity filled with nucleated protoplasm, and termed the embryo-sac, e, because the embryo is to be developed in it. ”

“ The ovule is attached to the placenta, and destined to become the seed. Ovules are most usually produced on the margins of the carpellary leaves, but are also formed over the whole surface of the leaf, as in Butomus. In other instances they rise The ovule. from the floral axis itself, either terminal, as in Polygonaceae and Piperaceae, or lateral, as in Primulaceae and Compositae. The ovule is usually contained in an ovary, and all plants in which the ovule is so enclosed are termed angiospermous ”

“ These are met with in all animals capable of reproduction, and they do not appear in the human species before puberty.
The ovule furnished by the female is existent in the 94ovary at the marriageable period. Fecundation takes place in the ovary; probably, sometimes, also in the tube or uterus when the ovule is passing out after menstruation.
Ordinarily the fluid ejaculated by the male must reach the uterus, and in some way be conveyed to the ovaries through the Fallopian tubes to produce fecundation. ”

“ This applies to trees, flowers, vegetables, fish, animals, birds, insects,—every living thing, including human beings. We have seen that the ovule from the ovary is the female egg, or principle. It is the part the female contributes toward the future child. Before a child is possible, however, the ovule must meet the egg from the male.
The Male or Papa Egg.—The male or papa egg is called a "spermatozoa." It reaches the interior of the womb through the lower opening, which you will remember opens into the vagina. ”

“ The unilocular ovaries, which are individually free, project considerably into the air around the gynobasic style; 1 ovule in each loculus; the fruitlets are drupes. Shrubs; leaves alternate, with stipules. Ochna; Ouratea.—160 species; tropical; especially American.
Order 8. Anacardiaceæ. The ovary rarely contains more than 1 ovule, even though there be several loculi and several carpels; in Anacardium all the 10 stamens except one become suppressed. ”

“ Curved ovules are found in Cruciferae, and Caryophyllaceae. The inverted or anatropous ovule (fig. 111) is the commonest form amongst angiosperms. In this ovule the apex with the micropyle is turned towards the point of attachment of the funicle to the placenta, the chalaza being situated at the opposite extremity; and the funicle, which runs along the side usually next the placenta, coalesces with the ovule and constitutes the raphe (r) , which often forms a ridge. ”

“ In some plants the ovary is divided into several compartments or cells, each with one or more ovules, which are only immature or unfertilized seeds, often very tiny, but usually quite easily seen if the ovary is cut open. It is the entrance of the pollen grain into this ovule that consummates the act of fertilization. As the ovule is carefully secreted within the ovary of the flower, and as the male fertilizing stuff or pollen is found only on the anther, it is obvious that some method of bringing the two together must be provided for. ”

“ At the time the ovule is ripening, the womb is preparing to receive it. This preparation consists of a reinforced blood supply brought to its lining. If fertilization takes place, the fertilized ovule or ovum will cling to the lining of the womb and there gather its nourishment. If fertilization does not take place, the ovum passes out of the body and the uterus throws off its surplus blood supply. ”

“ This nest and the tiny ovules are growing constantly from the time the girls are babies, but they grow so very slowly that none of the ovules are ripe until the girl is about twelve years old. After that one ripens every month and passes to the nest or womb. At the same time an extra amount of blood is sent to the womb to provide nourishing material for the ovule to use in its growth. ”

“ To study the embryo a series of young fruits should be selected, and the ovules carefully dissected out and mounted in water, to which a little caustic potash has been added. The ovule will be thus rendered transparent, and by pressing gently on the cover glass with a needle so as to flatten the ovule slightly, there is usually no trouble in seeing the embryo lying in the upper part of the embryo sac, and by pressing more firmly it can often be forced out upon the slide. ”

“ Ovary cut vertically, showing the numerous ovule* attached to the parietal placentae, the whole length of the ovary—magnified. 7. Ripe fruit, with valves of the capsule open, leaving the filiform, placentae still attached to the stigma—natural size. 8. Fruit cut transversely, showing the 5 placentas with their attached ovules—all more or less magnified. 9. A detached seed. ”

“ Upon being impregnated and the vesicle bursting, the ovum is grasped by the free extremity of the Fallopian tubes, which is in contact with the ovary, the ovum passes from the ovary to the canal, is pressed onwards by the peristaltic motions of the tube through the duct, and finally reaches the uterine cavity; there it continues to grow during the ordinary term of gestation. After two hundred and seventy days the ovule has developed into a child, and is expelled through the natural parts of generation. ”

“ Some authorities regard them as structures found only in the Phanerogams.
The ovule is thus a “monangic” (i.e. reduced to 1 sporangium, the nucellus) sorus, situated on a funicle, and enclosed by one or two cupular indusia, the integuments. Some of the ovules are erect (orthotropous) , others curved (campylotropous) , the majority reversed (anatropous) (Fig. 249) . ”

“ The most singular instances of morphological identity are those relating to the sexual organs. We have seen the gradual transition of stamens to pistils, and of pistils to stamens, the development of ovules on the edges of the anther, the co-existence of pollen with ovules on an antheroid body, and, stranger still, the actual development of pollen within the tissues of the ovule itself! ”

“ At this very early age of reproduction the embryo has all the elements of the future man or woman, mentally and physically, even before any form becomes apparent; and so small is the human being at the earliest stage of its existence that no material change is observable between the ovule that contains the product of conception and a fully developed ovule unimpregnated. ”

“ EARLY DEVELOPMENT
Some twelve days after conception, the female ovule or egg, which has been impregnated by the male spermatazoön, escapes from the ovary where it was impregnated, and entering a tube (Fallopian) gradually descends by means of it into the cavity of the womb or uterus. Here the little germ begins to mature in order to develop into an exact counterpart of its parents. In the human being the womb has only a single cavity, and usually develops but a single embryo. ”

“ Abortion of the ovules.—In the case of a pluri-ovulate ovary it rarely happens that all the ovules attain to maturity, some never get fertilised, others, pressed on by their neighbours on either side, become impeded in their development, and finally disappear, or remain as rudiments. ”

“ The ovary has many cavities with a large number of ovules attached to its walls, and is surmounted by a flat stigma of many radiating rows as in a poppy. The fruit is berry-like, and the seeds are remarkable for having their embryo surrounded by an endosperm as well as by a perisperm. ”

“ In the oak and hazel, an ovary with three and two cells respectively, and two ovules in each, produces a one-celled fruit with one seed. In the coco-nut, a trilocular and triovular ovary produces a one-celled, one-seeded fruit. This abortion may depend on the pressure caused by the development of certain ovules, or it may proceed from non-fertilization of all the ovules and consequent non-enlargement of the carpels. Again, by the growth of the placenta, or the folding inwards of parts of the carpels, divisions occur in the fruit which did not exist in the ovary. ”

“ Geo. J. Romanes.
From C. Darwin, Esq., to G. J. Romanes.
Down, Beckenham, Kent: March 26, 1881.
You are very plucky about Pangenesis, and I much wish that you could have any success. I do not understand your scheme. Do you intend to operate on an ovarium with a single ovule, and to bisect it after being fertilised? I should fear that this was quite hopeless. If you intend to operate on ovaria with many seeds, whether before or after fertilisation, I do not see how you could possibly distinguish any effect from the union of the two ovaria. ”

“ In each ovary are large numbers of cells, ovules, or eggs, one of which, at least, is supposed to pass into the uterine cavity with each menstruation. Anatomists tell us that each human ovary contains as many as 30,000 of these ovules, or eggs. ”

“ In a great many genera the number of ovules has been limited to one perfect one, which is placed in the central plane under the united leaf-edges, and sometimes also some barren ovules above it (Fig. 373) . The fruitlets in this case become achenes, and are present in much larger numbers than when there are follicles.
Fig. 374.—Helleborus niger: A flower; B receptacle; pet petals (honey-leaves) ; pi stamens and carpels; C seed; D anther (cross section) ; alb endosperm. ”

“ Disc surrounding the base of the ovary, cup-shaped or annular, 5-lobed or of 5 separate scales. Ovary superior, 1–10-celled but usually 5-celled; style simple, stigma usually capitate; ovules 1 or many in each cell, anatropous. ”

“ Not merely the degree of radial asymmetry of the ovary, but the number of its locules which have an odd number of ovules, seems to be of consequence in determining whether an ovary shall complete its development. Ovaries with even numbers—6, 8, 10, 12—of ovules in their locules have a better chance of developing to maturity than do those with one or more locules with an odd number. ”

“ The anomalous position of the stamens in front of the petals is explained by the abortion or non-development of an outer row of stamens, indications of which are sometimes seen on the hypogynous disk encircling the ovary. The ovary bears a sessile stigma and is more or less completely two-celled, with two erect ovules in each cell. ”