Word Finder - pollen

definition

A fine granular substance produced in flowers. Technically a collective term for pollen grains (microspores) produced in the anthers of flowering plants. (This specific usage dating from mid 18th century.)

definition

Fine powder in general, fine flour. (16th-century usage documented by the OED.)

example

"...and ther was good wyne of Gascoyne,... as well of pollen, as of other vitailes..." Froissart, Jean, 1338?-1410?; Berners, John Bourchier, Lord https//archive.org/details/chroniclefroiss00froigoog

definition

To cover with, or as if with, pollen.

Bees store honey and pollen to serve as food for their young.

A beekeeper, seeing the bee collect pollen from flowers and carry it to the hive, says that it exists to gather honey.

Bees feed on honey and pollen.

In Mirabilis Jalapa and others the filaments and style finally become intertwined, so that pollen is brought in contact with the stigma.

Limit the child's exposure to dust, pollen, and animal dander.

In these the pollen floats on the surface and reaches the stigmas of the female flowers as in Callitriche, Ruppia, Zostera, Elodea.

A male flower has floated alongside a female and one of its anthers, which have opened to set free the pollen, is in contact with a stigma.

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.

The flowers have an attractive floral envelope, are scented and often contain honey or a large amount of pollen by these means the insect is enticed to visit it.

In Broom there is an explosive machanism; the pressure of the insect visitor on the keel of the corolla causes a sudden release of the stamens and the scattering of a cloud of pollen over its body.

Sprengel came very near to appreciating the meaning of cross-pollination in the life of plants when he states that "it seems that Nature is unwilling that any flower should be fertilized by its own pollen."

Self-fertilization occurs when the pollen of a given flower affects the egg-cell of the same individual flower.

In the simplest instances the pollen of one flower fertilizes the ovules of another on the same plant, owing to the stamens arriving at maturity in any one flower earlier or later than the pistils.

The conveyance of pollen from one flower to another in crossfertilization is effected naturally by the wind, or by the agency of insects and other creatures.

The colour and markings of a flower often serve to guide the insects to the honey, in the obtaining of which they are compelled either to remove or to deposit pollen.

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.

In wind-fertilized plants the flowers are comparatively inconspicuous and devoid of much attraction for insects; and their pollen is smoother and smaller, and better adapted for transport by the wind, than that of insectfertilized plants, the roughness of which adapts it for attachment to the bodies of insects.

In a vinery, tomatohouse or a peach-house it is often good practice at the time of flowering to tap the branches smartly with a stick so as to ensure the dispersal of the pollen.

Sometimes more delicate and direct manipulation is required, and the gardener has himself to convey the pollen from one flower to another, for which purpose a small camel's-hair pencil is generally suitable.

To prevent self-fertilization, or the access of insects, it is advisable to remove the stamens and even the corolla from the flower to be impregnated, as its own pollen or that of a flower of the same species is often found to be " prepotent."

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.

Standard fruit trees must be left to take their chance; and, indeed from the lateness of their flowering, they are generally more injured by blight, and by drenching rains, which wash away the pollen of the flowers, than by the direct effects of cold.

They are usually included in Oomycetes, but their simple structure, minute size, usually uniciliate zoospores, and their negative characters would justify their retention as a separate group. It contains less than 200 species, chiefly parasitic on or in algae and other water-plants or animals, of various kinds, or in other fungi, seedlings, pollen and higher plants.

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 pollen is set free by the opening (dehiscence) of the anther, generally by means of longitudinal slits, but sometimes by pores, as in the heath family (Ericaceae), or by valves, as in the barberry.

If this is so, and the endosperm like the embryo is normally the product of a sexual act, hybridization will give a hybrid endosperm as it does a hybrid embryo, and herein (it is suggested) we may have the explanation of the phenomenon of xenia observed in the mixed endosperms of hybrid races of maize and other plants, regarding which it has only been possible hitherto to assert that they were indications of the extension of the influence of the pollen beyond the egg and its product.

A week earlier Mary, without waiting for the necessary papal dispensation (Pollen, Papal Negotiations with Mary Stuart), had publicly married Darnley, who bore the title of king, but never received the crown matrimonial.

Each cell is provided with a store of honey and pollen beside which an egg is laid; and after eight or nine cells have been successively built and stored, the whole is covered by a dome-like mass of cement.

If this "royal jelly" continue to be given to the grub throughout its life, it will grow into a queen; if the ordinary mixture of honey and digested pollen be substituted, as is usually the case from the fourth day, the grub will become a worker.

The numerous male catkins are generally arranged in dense whorls around the bases of the young shoots; the anther-scales, surmounted by a crest-like appendage, shed their abundant pollen by longitudinal slits; the two ovules at the base of the inner side of each fertile cone-scale develop into a pair of winged seeds, which drop from the opening scales when mature - as in the allied genera.

The leaves are rather short, curved, and often twisted; the male catkins, in dense cylindrical whorls, fill the air of the forest with their sulphur-like pollen in May or June, and fecundate the purple female flowers, which, at first sessile and erect, then become recurved on a lengthening stalk; the ovate cones, about the length of the leaves, do not reach maturity until the autumn of the following year, and the seeds are seldom scattered until the third spring; the cone-scales terminate in a pyramidal FIG.

The staminate contain 8 to 20 stamens which produce an enormous amount of dusty yellow pollen, some of which gets carried by wind to the protruding stigmas of the pistillate flowers.

The filaments elongate rapidly at flowering-time, and the lightly versatile anthers empty an abundance of finely granular smooth pollen through a longitudinal slit.

Thus the species' of wheat are usually selffertilized, but cross-fertilization is possible since the glumes are open above, the stigmas project laterally, and the anthers empty only about one-third of their pollen in their own flower and the rest into the air.

Pollination in cycads has always been described as anemophilous, but according to recent observations by Pearson on South African species it seems probable that, at least in some cases, the pollen is conveyed to the ovules by animal agency.

The stamens of the wheat plant may frequently be seen protruding beyond the glumes, and their position might lead to the inference that cross-fertilization was the rule; but on closer examination it will be found that the anthers are empty or nearly so, and that they are not protruded till after they have deposited the pollen upon the stigma.

The glumes have to be separated and the anthers cut away before the pollen is fully formed, care being taken at the same time not to injure the stigma, and specially not to introduce, on the scissors or otherwise, any pollen except that of the variety desired.

Thus, De Vilmorin records the presence of turgid wheats among seedlings raised from a common wheat fertilized with the pollen of a hard variety, and spelt wheats among the descendants of a common crossed with a turgid wheat.

The vertical section (A) shows the lower portion of the combs devoted to brood-rearing, the higher and thicker combs being reserved for honey, and midway between the brood and food is stored the pollen required for mixing with honey in feeding the larvae.

Launched upon an unknown world, and guided by unerring instinct to the very flowers it seeks, the bee fertilizes fruit and flowers while winging its happy flight among the blossoms, gathering pollen for the nurslings of its own home and honey for the use of man.

The earliest pollen is sought out from far and near, and has its immediate effect upon the mother bee of the colony.

It also shows sealed honey and pollen in cells, &c. To familiarize himself with the various objects depicted, all of which are drawn from nature, will not only help the reader to understand the different phases of bee-life during the swarming season, but tend to increase the interest of beginners in the pursuit.

If pollen is scarce, a substitute in the form of either pea-meal or wheaten flour must be supplied to the bees, as brood-rearing cannot make headway without the nitrogenous element indispensable in the food on which the young are reared.

Another indispensable feature of good bee-management is " forethought," coupled with order and neatness; the rule of where pollen (the fertilizing dust of flowers) is P (g)lentiful plentifu FIG.

In the early spring stores must be seen to and replenished where required; breeding stimulated when pollen begins to be gathered; and appliances cleaned and prepared for use during the busy season.

As the seed develops from the ovule which has been fertilized by the pollen, the essential structures for seed-production are two, viz.

The honey secreted by flowers attracts insects, which, by conveying the pollen to the stigma, effect fertilization.

The function of the stamen is the development and distribution of the pollen.

The anther consists of lobes containing the minute powdery pollen grains, which, when mature, are discharged by a fissure or opening of some sort.

The walls of the cells are frequently absorbed, so that when the anther attains maturity the fibres are alone left, and these by their elasticity assist in discharging the pollen.