On the Dispersal of Seeds by Mammals.
BY
H. N. RIDLEY, M.A., F.L.S.
THE relations of animals to plants in the matter of fertilization has been the subject of many hundred papers and books written by various observers, especially since DARWIN published his well-known researches. But the various modifications and adaptations of the seed and fruit for distribution by animals, although of almost equal im- portance in the evolution of new forms, has been very much neglected. No one can avoid being struck by the observation that there are a very large number of plants in some orders, which closely resemble each other in the form and colouring of the flowers and yet differ very materially in the fruit. In many of these cases it is the necessity of special adaptation for dispersal of the seed that is the cause of the various modi- fications of the fruit or seed. Seeds are, as is well known, dispersed by the aid of animals, either by being swallowed by them and afterwards passed from the body at some distance from the parent plant, or by adhering to their fur or feathers and so being borne away, or by being thrown to a distane by them, as will be explained later on. Or again they may be dispersed by the aid of wind or water, being in the first instance blown far from the tree, and in the latter case being drifted away by sea or river currents; and lastly they may be scatterd by merely mechanical means, as in the explosive capsules of the Castor-oil (Ricinus communis), and other Euphorbiaccous plants, or by merely rolling by their own weight when falling from the top of a lofty tree.
