of Science’ January 1842, there is an account of the pollen swept off the decks of a vessel.  Riley ’Fifth Report on the Noxious Insects of Missouri’ 1873 page 86.  Kerner ’Die Schutzmittel des Pollens’ 1873 page 6.  This author has also seen a lake in the Tyrol so covered with pollen, that the water no longer appeared blue.  Mr. Blackley ‘Experimental Researches on Hay-fever’ 1873 pages 132, 141-152.) Considering these facts, it is not so surprising as it at first appears that all, or nearly all, the stigmas of anemophilous plants should receive pollen brought to them by mere chance by the wind.  During the early part of summer every object is thus dusted with pollen; for instance, I examined for another purpose the labella of a large number of flowers of the Fly Ophrys (which is rarely visited by insects), and found on all very many pollen-grains of other plants, which had been caught by their velvety surfaces.

The extraordinary quantity and lightness of the pollen of anemophilous plants are no doubt both necessary, as their pollen has generally to be carried to the stigmas of other and often distant flowers; for, as we shall soon see, most anemophilous plants have their sexes separated.  The fertilisation of these plants is generally aided by the stigmas being of large size or plumose; and in the case of the Coniferae, by the naked ovules secreting a drop of fluid, as shown by Delpino.  Although the number of anemophilous species is small, as the author just quoted remarks, the number of individuals is large in comparison with that of entomophilous species.  This holds good especially in cold and temperate regions, where insects are not so numerous as under a warmer climate, and where consequently entomophilous plants are less favourably situated.  We see this in our forests of Coniferae and other trees, such as oaks, beeches, birches, ashes, etc.; and in the Gramineae, Cyperaceae, and Juncaceae, which clothe our meadows and swamps; all these trees and plants being fertilised by the wind.  As a large quantity of pollen is wasted by anemophilous plants, it is surprising that so many vigorous species of this kind abounding with individuals should still exist in any part of the world; for if they had been rendered entomophilous, their pollen would have been transported by the aid of the senses and appetites of insects with incomparably greater safety than by the wind.  That such a conversion is possible can hardly be doubted, from the remarks lately made on the existence of intermediate forms; and apparently it has been effected in the group of willows, as we may infer from the nature of their nearest allies. (10/55.  Hermann Muller ‘Die Befruchtung’ etc. page 149.)