On the Dispersal of Seeds by Mammals 



BY 



H. N. RIDLEY, m.a., f.l.s. 



® 



HE relations of animals to plants in the matter of 

 I 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 distance 

 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 comniunis)^ and other 

 Euphorbiaceous plants, or by merely rolling by their own 

 weight^vhen falling from the top of a lofty tree. 



