Definition: token of disgrace; brand; V. stigmatize: mark with a stigma; characterize as disgraceful
Definition: token of disgrace; brand; V. stigmatize: mark with a stigma; characterize as disgraceful
Sentences Containing 'stigma'
Insects act like a camel-hair pencil, and it is sufficient, to ensure fertilisation, just to touch with the same brush the anthers of one flower and then the stigma of another; but it must not be supposed that bees would thus produce a multitude of hybrids between distinct species; for if a plant's own pollen and that from another species are placed on the same stigma, the former is so prepotent that it invariably and completely destroys, as has been shown by Gartner, the influence of the foreign pollen.
In numerous other cases, far from self-fertilisation being favoured, there are special contrivances which effectually prevent the stigma receiving pollen from its own flower, as I could show from the works of Sprengel and others, as well as from my own observations: for instance, in Lobelia fulgens, there is a really beautiful and elaborate contrivance by which all the infinitely numerous pollen-granules are swept out of the conjoined anthers of each flower, before the stigma of that individual flower is ready to receive them; and as this flower is never visited, at least in my garden, by insects, it never sets a seed, though by placing pollen from one flower on the stigma of another, I raise plenty of seedlings.
In very many other cases, though there is no special mechanical contrivance to prevent the stigma receiving pollen from the same flower, yet, as Sprengel, and more recently Hildebrand and others have shown, and as I can confirm, either the anthers burst before the stigma is ready for fertilisation, or the stigma is ready before the pollen of that flower is ready, so that these so-named dichogamous plants have in fact separated sexes, and must habitually be crossed.
Yet the pistil of each cabbage-flower is surrounded not only by its own six stamens but by those of the many other flowers on the same plant; and the pollen of each flower readily gets on its stigma without insect agency; for I have found that plants carefully protected from insects produce the full number of pods.
With plants having separated sexes, and with those in which, though hermaphrodites, the pollen does not spontaneously fall on the stigma, some aid is necessary for their fertilisation.
With several kinds this is effected by the pollen-grains, which are light and incoherent, being blown by the wind through mere chance on to the stigma; and this is the simplest plan which can well be conceived.
An almost equally simple, though very different plan occurs in many plants in which a symmetrical flower secretes a few drops of nectar, and is consequently visited by insects; and these carry the pollen from the anthers to the stigma.
The passage is narrow, and is roofed over by the column, so that a bee, in forcing its way out, first rubs its back against the viscid stigma and then against the viscid glands of the pollen-masses.
When the bee, thus provided, flies to another flower, or to the same flower a second time, and is pushed by its comrades into the bucket and then crawls out by the passage, the pollen-mass necessarily comes first into contact with the viscid stigma, and adheres to it, and the flower is fertilised.
Now at last we see the full use of every part of the flower, of the water-secreting horns of the bucket half-full of water, which prevents the bees from flying away, and forces them to crawl out through the spout, and rub against the properly placed viscid pollen-masses and the viscid stigma.
The pollen-mass of the male plant (for the sexes are separate in this orchid) is thus carried to the flower of the female plant, where it is brought into contact with the stigma, which is viscid enough to break certain elastic threads, and retain the pollen, thus effecting fertilisation.
The pollinia are by this means transported by insects from one flower to the stigma of another.
In most flowers belonging to other orders the stigma secretes a little viscid matter.
Now, in certain orchids similar viscid matter is secreted, but in much larger quantities by one alone of the three stigmas; and this stigma, perhaps in consequence of the copious secretion, is rendered sterile.
From this simple condition, which differs but little from that of a multitude of common flowers, there are endless gradations--to species in which the pollen-mass terminates in a very short, free caudicle--to others in which the caudicle becomes firmly attached to the viscid matter, with the sterile stigma itself much modified.
In this, and in almost every other case, the enquiry may be pushed further backwards; and it may be asked how did the stigma of an ordinary flower become viscid, but as we do not know the full history of any one group of beings, it is as useless to ask, as it is hopeless to attempt answering, such questions.
When pollen from a plant of one family is placed on the stigma of a plant of a distinct family, it exerts no more influence than so much inorganic dust.
From this absolute zero of fertility, the pollen of different species applied to the stigma of some one species of the same genus, yields a perfect gradation in the number of seeds produced, up to nearly complete or even quite complete fertility; and, as we have seen, in certain abnormal cases, even to an excess of fertility, beyond that which the plant's own pollen produces.
It has also been observed that when the pollen of one species is placed on the stigma of a distantly allied species, though the pollen-tubes protrude, they do not penetrate the stigmatic surface.
These organs are so proportioned in length to each other that half the stamens in two of the forms stand on a level with the stigma of the third form.
Now I have shown, and the result has been confirmed by other observers, that in order to obtain full fertility with these plants, it is necessary that the stigma of the one form should be fertilised by pollen taken from the stamens of corresponding height in another form.
It is well known that if pollen of a distinct species be placed on the stigma of a flower, and its own pollen be afterwards, even after a considerable interval of time, placed on the same stigma, its action is so strongly prepotent that it generally annihilates the effect of the foreign pollen; so it is with the pollen of the several forms of the same species, for legitimate pollen is strongly prepotent over illegitimate pollen, when both are placed on the same stigma.
The pistil consists of a stigma supported on the style; but in some Compositae, the male florets, which of course cannot be fecundated, have a rudimentary pistil, for it is not crowned with a stigma; but the style remains well developed and is clothed in the usual manner with hairs, which serve to brush the pollen out of the surrounding and conjoined anthers.
The pistil is generally divisible into the ovary or germen, the style and the stigma.
This impregnation is brought about by means of tubes (POLLEN-TUBES) which issue from the pollen-grains adhering to the stigma, and penetrate through the tissues until they reach the ovary.
In 2002 the term for schizophrenia in Japan was changed from "Seishin-Bunretsu-Byō" 精神分裂病 (mind-split-disease) to "Tōgō-shitchō-shō" 統合失調症 (integration disorder) to reduce stigma.
In addition, NAMI Greater Houston strives to eliminate pervasive stigma, to effect positive changes in the mental health system and to increase public and professional understanding about mental illness.
The anthers and stigma are present in a whorl like mound at the center of the flower in a dusty yellow coloring.
Flowers are hermaphrodite, in inflorescences about 3–10 cm; pedicelate about 2–5 mm, yellow greenish, pubescent and fleshy tepals, the style ends in a papilose and obtuse stigma.
Its stated purpose is to promote lung cancer awareness, reduce lung cancer mortality and end the stigma associated with lung cancer.
Lung Cancer Alliance was founded in 1995 with to meet the needs of lung cancer patients and those at risk by improving outcomes, eliminating stigma and securing public health research funding.
In June 2012, it launched its national “No One Deserves To Die” campaign to help raise awareness and change the stigma associated with lung cancer.
The Public Petition Committee reported to the House on 10 July (i.e. the day after the by-election) and recommended that the Government pass a bill to remove the stigma of disqualification.
Audism is the notion that one is superior based on one's ability to hear or to behave in the manner of one who hears, or that life without hearing is futile and miserable, or an attitude based on pathological thinking which results in a negative stigma toward anyone who does not hear.
There is a small black stigma and a dark diagonal line running from the apex to the inner margin.
Kass further pointed out that targeting may create stigma that some segments of the population are more vulnerable to certain diseases, which might result in social harms, such as psychological distress and discrimination.
This stigma may create anxiety and panic among the targeted population.
There is a stigma attached to doing a reverse stock split, as it underscores the fact that shares have declined in value, so it is not common and may take a shareholder or board meeting for consent.
The refusal to fight in the war against the Silicates has led to a stigma that continues to haunt In Vitroes everywhere, years after that particular war ended.
With the resources of PhatAhDat, Vigalantee also pioneered the No Jaangle Movement, a social consciousness movement that challenges young people to combat the stigma of "bojangling," a negative stereotype that haunts most minority youths.
Soon after the loss, Gerard successfully managed to manipulate "technico" Shane Storm into aligning with him, effectively renaming him STIGMA.
Gerard and STIGMA would feud with The Colony until September 7, when the two aligned with the returning Colin Delaney to form the UnStable, and thus evening the numbers of both groups.
The NMD is organized to protest against social stigma against masturbation.
This breakthrough was reported worldwide, and led to a reduction in the stigma attached to leprosy, and consequent better treatment of patients, at the time still referred to as "inmates", and forbidden from using public transport.
Pyrenoids may be present or absent, the stigma large.
By the end of the follicular, or proliferative, phase of the thirteenth day of the menstrual cycle, the cumulus oophorus layer of the preovulatory follicle will develop an opening, or "stigma", and excrete the oocyte with a complement of cumulus cells in a process called ovulation.
Several in the group have an association with the University of Pennsylvania, and have an interest in seeing the valuable but understudied skull collection freed from the stigma of bias."
Each flower has its own stamens and its own stigma but the lobes of the stigma remain closed until after the anthers have opened and discharged their pollen; after they have withered and become effete then the stigma opens and invites the wandering bee.
The immediate distinguishing feature of "Pyrola" species is the flower style which is often curved, sticks out beyond the petals and is expanded below the stigma which itself is branched into several lobes.
The rather large and complex stigma may be an adaptation to ensure that small insects carrying pollen have an attractive landing place.
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