Defn: The part of a pistil or fruit to which the ovules or seeds are attached.
It consists of an ovary, containing the ovules or rudimentary seeds, and a stigma, which is commonly raised on an elongated portion called a style.
Defn: One of a class of plants, so called by Lindley, because the ovules are fertilized by direct contact of the pollen.
Defn: Direct fertilization in plants, as when the pollen fertilizing the ovules comes from the stamens of the same blossom; -- opposed to heterogamy.
Defn: That part of the ovary from which the ovules arise; the placenta.
An embryo sac or embryonal vesicle in the ovules of flowering plants.
The greater part of theovules prove abortive, but those that ripen retain their calyx, though they remain embedded in the pulp.
The ovary when young has two cells and two ovules (as shown at g); but the division between the cells wastes away as the seeds ripen, and one of the ovules proves abortive.
The female catkins consist of six scales, with two ovules at the base of each; and the ripe cone has a sharp point projecting from each scale.
The pollen, when absorbed by the stigma, is conveyed down the style to the ovary, where it falls upon and fertilises the ovules or incipient seeds.
There are two ovulesin each cell, placed side by side, but generally only one seed in each becomes perfectly ripe.
As in the preceding genera, however, many of these ovules become abortive; and as the cells fill gradually with cellular pulp, the seeds become detached from the placenta, and buried in it.
The distinguishing trait of the higher plants that form the grand division known as Angiosperms, is that the ovules are borne in a closed ovary, and the pollen lodges on the end of a stigma.
Contact of pollen grains and nakedovules is followed by their coalescence--the "setting of seeds.
Among the youngest leaves, toward the end of the shoot, the purplish rosy lips of the erect pistillate cone-flowers catch the dust from neighbor trees, and their naked ovules absorb it and set seed.
Close shut are the lips again, against any other invasion, while these ovules mature.
The naked ovules are borne on the scales of the fertile spike or catkin, which is held apart and erect in blossoming time.
It should also be observed that in sexual generation, the ovules and the male element have equal power of transmitting every single character possessed by either parent to their offspring.
If, on the other hand, pollen which included the elements of one species happened to unite withovules including the elements of the other species, the intermediate or hybrid state would still be retained, and there would be no reversion.
So that, with these illegitimate unions, the act of impregnation is less assured, and the fertility slightly less, when the pollen and ovules belong to the same flower, than when belonging to two distinct individuals of the same form.
The structure of many of the lower animals, when they are hermaphrodites, is such as to prevent the ovules being fertilised by the male element of the same individual; so that the concourse of two individuals is necessary.
It is also interesting to observe on how slight a difference in the nature of the pollen or of the ovules complete self-sterility or complete self-fertility must depend in some of the above cases.
But many exotic plants, with their ovules and pollen appearing perfectly sound, will not set any seed.
I may here add that although ovulescan be detected in most or all female animals at an extremely early age, there is no reason to doubt that gemmules derived from parts modified during maturity can pass into the ovules.
This self-impotence does not depend on the pollen or ovules being in an unfit state for fertilisation, for both have been found effective in union with other plants of the same or of a distinct species.
This has also occurred with a plant of Saxifraga geum, in which a series of adventitious carpels, bearing ovules on their margins, had been developed between the stamens and the normal carpels (18/94.
Maxwell Masters have found pollen within the ovulesof the passion-flower and of the rose.
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.
The placentas are parietal, and the ovules appear sessile on the walls of the ovary.
The ovules (o) are attached to a free central placenta, which has no connexion with the walls of the ovary.
But in Primulaceae no vestiges of septa or marginal ovules can be perceived at any period of growth; the placenta is always free, and rises in the centre of the ovary.
When there are two ovules in the same cell, they may be either collateral, that is, placed side by side (fig.
The ovules (o) are attached to a central placenta, formed by the union of the five ventral sutures.
Diagrammatic section of a five-carpellary ovary, in which the edges of the carpels, bearing the placentas and ovules o, are not folded inwards.
The same cut horizontally, and the halves separated so as to show the interior of the cavity of the ovary o, with the free central placenta p, covered with ovules g.
The carpellary leaves are sometimes united in such a way as to leave an opening at the apex of the pistil, so that the ovules are exposed, as in mignonette.
In Cycas the carpels are ordinary leaves, with ovules upon their margin.
In all the genera, except Cycas itself, the female fructifications are likewise cones, each carpel bearing two ovules on its margin.
There is thus an approach to the closed pistil of an Angiosperm, but it is evident that the ovules received the pollen directly.
The Bennettiteae, at any rate, were still at the gymnospermous level as regards their pollination, for the exposed micropyles of the ovules were in a position to receive the pollen directly, without the intervention of a stigma.
The number of the seeds produced is smaller and the ovules larger, probably also fewer in number.
Ovary with many ovules in each cell; style and sometimes the stigmas one.
Ovules a pair in each cell, suspended, with the rhaphe dorsal (turned away from the placenta).
Ovules 2 or more at the base of each scale, erect.
Ovules and seeds numerous on each placenta; corolla rotate-campanulate, with 10 vertical lamellae within.
Ovules and seeds 2--8 on each placenta; corolla rotate or campanulate, with entire lobes and no appendages.
Fertile catkins solitary or aggregated immediately below the terminal bud, or lateral on the young shoot, consisting of imbricated carpellary scales, each in the axil of a persistent bract, bearing a pair of inverted ovules at the base.
These "sports" are extremely rare under nature, but far from rare under cultivation; and in this case we see that the treatment of the parent has affected a bud or offset, and not the ovules or pollen.
Thus in plants, the office of the pistil is to allow the pollen-tubes to reach the ovules protected in the ovarium at its base.
TWINS Sometimes two ovulesare matured at the same time.
Triplets and quadruplets, the results of the maturing of three or four ovules at the same time, occur more rarely.
Thus some of the ovules of the white flowers received an impression of red from the pollen of the red flowers, and grew into red flowering plants.
It is indeed one of the most necessary parts of the flower, for without it the ovules could not develop.
When the child discovers that the ovules are attached to the ovary by little stems, this very important question can be answered,--How are the ovules nourished?
These received the pollen on the stigma, and in some way this pollen affected the ovules so that they began to develop.
While the cross-fertilization of the same order of plants is so desirable, it is not possible for the pollen of one order to fertilize the ovules of another order.
Look at the pod against the light and see the ovules dimly outlined.
The sap, which is the food of the plant, runs through the little stems that hold the ovules to the ovary, and thus, entering the ovules, nourishes them.
From the inside of each ovary the tiny eggs, or ova, grow, just as the ovules grow in the plant ovary or seed-pod.
After the ovules have been fertilized, the ovary is called a =pericarp=.
On examination of the ovaries after slaughtering, it was found that in the case of one of the carbonaceous fed hens the ovules were in a more advanced stage, but on the whole the nitrogenous fed hens were much nearer the laying period.
With this single exception, the clusters of ovules in the carbonaceous fed hens were uniformly small.
From time to time some of these ovules enlarge and are surrounded by a vesicle with liquid contents, which is called the Graafian follicle.
In the right ovary are seen ovules in various degrees of maturity in their Graafian follicles: also a corpus luteum--an empty Graafian follicle after expulsion of the ovule.
Moreover, there are women who never menstruate and who, in spite of this, not only regularly discharge ovules but may be fecundated and become pregnant.
A certain amount of sperm is deposited by the male in the neighborhood of the mature ovules (Fig.
Puberty takes place a little earlier in women than in men, and corresponds to the growth of the internal and external sexual organs, at the same time that the ovules commence to mature and menstruation is established.
Axillary, [Illustration] ovules attached to a central column in a compound ovary.
Parietal, [Illustration] ovulesattached to the outer walls of the ovary.
Placentæ, the parts to which the ovules are attached.
Sometimes as in species of Trifolium and Medicago the ovulesare reduced to one.
In every ovary there are several hundred little ovules or eggs in various stages of development.
At irregular intervals one of these ovules ripens and leaves the ovary.
A class of flowering plants, in which the ovules are not inclosed in an ovary.
A term applied to all flowering plants in which the ovules are inclosed in an ovary, and the seeds in a pericarp or covering, as in all flowering plants except those mentioned under gymnosperms and gymnogens, which see.
He traced the development of the cavity of the ovary and regarded the ovules as reduced to their simplest expression--to an "amnios" or embryo-sac.
Griffith also examined the ovules of Osyris recognising the corresponding facts.
He describes in the Notulae his observations on the ovules and pollination of various Coniferae and Gnetaceae.
To sum up Griffith's work on the morphology of the reproductive organs of the Angiosperms we see that he added many important facts and gave correct descriptions of what still remain among the most anomalous ovules and embryos.
The archegonia he describes as ovuleswithout envelopes consisting of a papilla (the neck) which becomes perforated, giving the spermatozoid access to the embryo-sac within.
These frantic efforts would end in exhaustion if kept up too long, and before that happens, but after the impregnated ovules have no further use for the flies, the anthers give forth plentiful supplies of pollen.
In the chapter on “How Plants Produce Their Young,” we found that most flowering plants have their ovules in an ovary which, after fertilization, develop into fruit and seed.
If a plant had the ovules erect, the stigmata divided, possessed the albumen, and was without stipules, it possibly would not be classed among the Rosaceæ.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "ovules" in a variety of sentences. We hope that you will now be able to make sentences using this word.
