The pistil consists of a single carpel with its ovary, style, stigma and solitary ovule or twin ovules.
Pollen may be transferred to the stigma of the same flower - self-pollination (or autogamy), or to the stigma of another flower on the same plant or another plant of the same species - crosspollination (or allogamy).
Stg, Stigma or orifice of the hollow tendons of the branchial plates of Limulus.
S, Prosomatic stigma or aperture of the tracheal system.
Prosoma and opisthosoma; a, tracheal stigma; b, last somite.
The ovary bears a sessile stigma and is more or less completely two-celled, with two erect ovules in each cell.
As in all poplars, the catkins expand in early spring, long before the leaves unfold; the ovaries bear four linear stigma lobes; the capsules ripen in May.
But reasonable judgment must find very unjust the stigma of duplicity put upon him by the Federalists.
In other cases (some larvae) stigmata are absent; in other cases again a single stigma is developed, as in the smaller Arachnida and Chilopoda, in the median dorsal line or other unexpected position.
Regarded without republican sympathies, and in the light of 18th-century doctrines of allegiance, his acts, however severe, in no way deserve the stigma of cruelty ordinarily put upon them.
From the city, takes the place of workhouses, and has many cottages in which live those of the city's poor who were formerly classed as paupers and were sent to poorhouses, and who now apply their labour to the farm and are relieved from the stigma that generally attaches to inmates of poorhouses.
Some or all of the anthers become twisted so that insects in probing for honey will touch the anthers with one side of their head and the capitate stigma with the other.
The anthers are so situated that the pollen on escaping comes into contact with the stigma; in such flowers self-fertilization is compulsory and very effectual, as seeds in profusion are produced.
The elongated axis which opens at the stigma in Scorpio and which can be cleared of soft, surrounding tissues and co agulated blood so as to present the appearance of a limb axis carrying the book-like leaves of the lung is not really, as it would seem to be at first sight, the limb axis.
2nd) somite (Opiliones) of the opisthosoma, there being rarely an additional stigma on the 4th (some Solifugae).
,?, VI B, Ventral view of the prosoma and of the first somite of the opisthosoma, with the appendages I to VI cut off at the base; a, tracheal stigma; mx, maxillary processes of the coxae of the 3rd pair of appendages; g,genital aperture.
The ten thousand known species included in this group agree with the Cynipoidea and Chalcidoidea in the position of the ovipositor and in the jointed trochanters, but are distinguished by the fore-wing possessing a distinct stigma and usually a typical series of nervures and areolets (figs.
* The term homogamy is applied to the simultaneous maturity of stigma and anthers.
In very many cases the pollen is carried to the stigma by elongation, curvature or some other movement of the filament, the style or stigma, or corolla or some other part of the flower, or by correlated movements of two or more parts.
The excesses of John of Leiden, the Brigham Young of that age, cast an unjust stigma on the Baptists, of whom the vast majority were good, quiet people who merely carried out in practice the early Christian ideals of which their persecutors prated.
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.
These latter unfairly attempted to fix the stigma of the Quartodeciman observance on the British and Celtic churches, and they are even now sometimes ignorantly spoken of as having followed the Asiatic practice as to Easter.
The object of these movements will be appreciated when it is remembered that, if the pollen-masses retained the original direction they had in the anther in which they were formed, they would, when transported by the insect to another flower, merely come in contact with the anther of that flower, where of course they would be of no use; but, owing to the divergences and flexions above alluded to, the pollen-masses come to be so placed that, when transplanted to another flower of the same species, they come in contact with the stigma and so effect the fertilization of that flower.
Owing, however, to the close proximity of stigma and anthers, very slight irregularity in the movements of the visiting insect will cause self-pollination, which may also occur by the dropping of pollen from the anthers of the larger stamens on to the stigma.
The proboscis, passing down this groove to the spur, becomes dusted with pollen; as it is drawn back, it presses up the lip-like valve of the stigma so that no pollen can enter the stigmatic chamber; but as it enters the next flower it leaves some pollen on the upper surface of the valve, and thus cross-fertilization is effected.
P, a thickened line on the walls forming the placenta; c, calyx; d, ovary; s, hooded stigma terminating the short style.
Terminating the short annual shoot which bears a whorl of four or more leaves below the flower; in this and in some species of the nearly allied genus Trillium (chiefly temperate North America) the flowers have a fetid smell, which together with the dark purple of the ovary and stigmas and frequently also of the stamens and petals, attracts carrion-loving flies, which alight on the stigma and then climb the anthers and become dusted with pollen; the pollen is then carried to the stigmas of another flower.
The style is simple or branched, and the stigma is linear, capitate or globose in form; these variations afford means for distinguishing the different genera.
The cup-shaped flowers have six regular segments in two rows, as many free stamens, and a three-celled ovary with a sessile stigma, which ripens into a leathery many-seeded capsule.
POLLINATION, in botany, the transference of the pollen from the stamen to the receptive surface, or stigma, of the pistil of a flower.
Has ceased to be receptive before the anthers open, or the anthers have withered before the stigma becomes receptive, when crosspollination only is possible, or the stages of maturity in the two organs are not so distinct, when self-pollination becomes possible later on.
Spontaneous self-pollination is rendered impossible in some homogamous flowers in consequence of the relative position of the anthers and stigma - this condition has been termed herkogamy.
In many cases pollen has no effect on the stigma of the same flower, the plants are selfsterile, in other cases external pollen is more effective (pre-potent) than pollen from the same flower; but in a very large number of cases experiment has shown that there is little or no difference between the effects of external pollen and that from the same flower.
(X 6 times.) The dotted lines with the arrow show the directions in which pollen must be carried to each stigma to ensure full fertility.
Even in homogamous flowers cross-pollination is in a large proportion of cases the effective method, at any rate at first, owing to the relative position of anther and stigma or the fact that the plant is self-sterile.
Many plants produce, in addition to ordinary open flowers, so-called cleistogamous flowers, which remain permanently closed but which notwithstanding produce fruit; in these the corolla is inconspicuous or absent and the pollen grows from the anther on to the stigma of the same flower.
In small flowers which are crowded at the same level or in flat flowers in which the stigmas and anthers project but little, slugs or snails creeping over their surface may transfer to the stigma the pollen which clings to the slimy foot.
8) which facilitate adhesion to some part of the insect's body, and a relatively small stigma with a sticky surface.
It derives its scientific name from a curious beak-like appendage at the end of the stigma, in the centre of the flower; this appendage though solid was supposed to be hollow (hence the name from 46a, a bladder, and stigma).
Self-pollination is rendered possible, since the divisions of the stigma begin to separate before the outer stamens have shed all their pollen; the nearness of the stigmas to the dehiscing anthers favours self-pollination.
It is a singular circumstance that reciprocal crosses are not always or even often possible; thus, one rhododendron may afford pollen perfectly potent on the stigma of another kind, by the pollen of which latter its own stigma is unaffected.
The conidia are fragrant and are carried by bees to the stigma of the bilberry; here they germinate with the pollen and the hyphae pass with the pollen tubes down the style; the former infect the ovules and produce sclerotia, therein reducing the fruits to a mummified condition.
The carpel, or aggregate of carpels forming the pistil or gynaeceum, comprises an ovary containing one or more ovules and a receptive surface or stigma; the stigma is sometimes carried up on a style.
When placed on the stigma, under favourable circumstances, the pollen-grain puts forth a pollen-tube which grows down the tissue of the style to the ovary, and makes its way along the placenta, guided by projections or hairs, to the mouth of an ovule.
The stamens are diadelphous, nine of them being united by their filaments f, while the uppermost one (e) is free; st, stigma, c, calyx.
The very long and apparently simple stigma of maize arises from the union of two.
The presence of a perianth is a feature suggestive of an approach to the floral structure of Angiosperms; the prolongation of the integument furnishes the flowers with a substitute for a stigma and style.
In function the perianth may be compared with a unilocular ovary containing a single ovule; the projecting integument, which at the time of pollination secretes a drop of liquid, serves the same purpose as the style and stigma of an angiosperm.
The integument of the sterile ovule is prolonged above the nucellus as a spirally-twisted tube expanded at its apex into a flat stigma-like organ.
Stigma; co, costa.
4, 2) has no stigma, but one or two areolets.
Botanists were for a long time content to know that the scattering of the pollen from the anther, and its application to the stigma, were necessary for the production of perfect seed, but the stages of the process of fertilization remained unexplored.
In many cases the slimy masses of spermatia (Uredineae), conidia (Claviceps), basidiospores (Phallus, Coprinus), &c., emit more or less powerful odours, which attract flies or other insects, and it has been shown that bees carry the flagrant oidia of Sclerotinia to the stigma of Vaccinium and infect it, and that flies carry away the foetid spores of Phallus, just as pollen is dispersed by such insects.
The superior ovary - half-inferior in Samolus - bears a simple style ending in a capitate entire stigma, and contains a free-central placenta bearing generally a large number of ovules, which are exceptional in the group Gamopetalae in having two integuments.
The great bazar at Kabul was blown up with gunpowder to fix a stigma upon the city; the prisoners were recovered; and all marched back to India, leaving Dost Mahommed to take undisputed possession of his throne.
In his book on the fertilization of flowers, Hermann Muller distinguishes four types of papilionaceous flowers according to the way in which the pollen is applied to the bee: (I) Those in which the stamens and stigma return within the carina and thus admit of repeated visits, such are the clovers, Melilotus and laburnum.