Pollination
The dusting of the stigma of a flower with pollen grains, as distinguished from fertilisation, or the action of the pollen upon the ovule, which gives rise to the development of the seed containing an embryo. Pollination must precede fertilisation. It is effected in very different ways in different flowers, and the agents by which it is effected are manifold. The more important of these are here indicated; but the account must be brief, though volumes have been written upon the subject of Pollination. Full information of the present state of our knowledge of the matter will be found in Dr. H. Muller's "Fertilisation of Flowers," translated by Prof. W. D' A. Thompson; Darwin's "Fertilisation of Orchids;" and Kerner's "Flowers and their Unbidden Guests," translated by Dr. Ogle. Sir John Lubbock's "British Wild Flowers in Relation to Insects" contains much interesting information regarding the subjects indicated in the title. There are also many shorter works and articles upon Pollination published in most European languages of late years. A list of these, compiled by Prof. Thompson, is included in Muller's work referred to above, and includes almost all published up to 1883. The method of Pollination varies with the structure of the flower. In those plants in which the pollen and the ovules of the same flower ripen simultaneously, the pollen may be transferred directly from the anthers to the stigma either by the parts lying in contact, or by their lying in such a position that the pollen falls from the anthers upon the stigma. In cleistogamous flowers, or those (e.g., in Sweet Violets, Wood Sorrel) which, in certain plants, are formed in summer and autumn, and never open, but yet are often more productive of seeds than the conspicuous flowers, the pollen, while in the anthers, pushes pollen tubes to the stigma, which is thus