581.95 i86 



V. 



D ispers al of Seeds l3y Birds. 



THE dispersal of seeds to a place where they can germinate and 

 develop is to a plant a matter of almost as great importance as 

 the cross-fertilisation of the flower ; and the modifications of the 

 plant to ensure this end are worthy of more attention than has been 

 paid to them. It is a subject which must be studied in the field, for, 

 otherwise, many important points in the structure of the fruit or seed 

 may not be intelligible. I have already published, in the Jomnal of the 

 Straits Asiatic Society, vol. xxiv., p. lo, 1893, ^^ account of the means 

 of seed-dispersal by mammals in the Malay Peninsula, and I propose 

 here to continue those notes by accounts of the other means by which 

 seeds are disseminated, viz., by the aid of birds and insects, by wind, 

 by streams and sea. 



The subject has naturally a considerable bearing on the geo- 

 graphical distribution of plants, but I believe its value in this 

 direction has been often over-rated. I have already {loc. cit.) pointed 

 out that it is not to the advantage of any plant that its seeds should 

 be borne to a very great distance, and I shall show that, except in the 

 case of sea-borne seeds, the distance to which they are usually borne, 

 and the journey for- which they are modified, are really very short, and 

 although numerous exceptions occur in which seeds are known to 

 have been carried very far by natural causes, this is not the rule. 



The study shows, not only how certain plants are found in certain 

 localities, but also why certain groups are absent. Nothing in the 

 distribution of orders in the Malay Peninsula is more striking than 

 the paucity of Compositae. Now, the Compositae are a group in which 

 the calyx is usually developed into a plume, by which the fruit is 

 borne along by the wind. They are nearly all low herbs, so that, 

 when ripe, the fruits are drifted along at no great height above the 

 ground ; they thus require open country for the dispersal of their 

 seed, for a dense jungle, such as is common in tropical countries — 

 especially if fringed, as it often is, with a tangled mat of creepers — 

 stops the drifting seeds immediately at its edge. A clearing in such 

 a jungle, if there is no direct communication with the open country, 

 will remain free from plants of this character, but if a pathway of 

 sufficient breadth is cut from the plain to the clearing, these plants 



