i02 A NATURALIST IN THE PACIFIC chap. 



his memoir on the flora of Kinabalu observes in this connection 

 that the fact that a fruit is fleshy and attractive to birds is " no 

 proof that it is really devoured by them, and still less that it is 

 dispersed by them." Neither in fleshy fruits, nor in minute seeds, 

 nor in seeds capable of being transported by the wind does he 

 regard the general object of the particular character as primarily 

 to act as a means of dispersion. 



The same plea is made for the mucosity of seeds like those 

 of Capsella and Plantago (see Note 43), or for the " stickiness " of 

 other seeds and fruits like those of Pisonia, qualities that favour 

 adherence to passing objects. This is the reason, we are told, why 

 seeds are " sticky." Such secretions I infer are often materials lost 

 to the plant ; and being in that sense excretory we are not called 

 on to supply a use for them. They can, therefore, not be regarded 

 as having any teleological significance, since adaptation arises only 

 from the requirements of the plant's conditions of existence. If 

 they are serviceable in assisting the distribution of seeds, such an 

 event can only be described as an accident in the plant's life arising 

 from chance contact with another environment. 



The appendages of seeds and fruits, such as hooks and hairs, 

 that render them liable to adhere to fur or feathers, are also 

 regarded as special adaptations to this end. Without entering into 

 the physiological significance of hairs and prickles generally, con- 

 cerning which, as many of my readers will know, much might be 

 said not in favour of such a view, I would refer to cases like that ol 

 Caesalpinia Bonducella, where the large prickly pods could not 

 possibly be intended to aid the plant's dispersal, whilst the leaf- 

 branches are also prickly, and the seeds are well known to be dis- 

 tributed by the currents. There are other cases like that of Bidens 

 cernua where the achenes, by reason of their barbed bristles, and on 

 account of a layer of " buoyant tissue " in the fruit-coats, are dis- 

 persed both by birds and by water. We may fitly ask to which 

 capacity the theory of adaptation should be applied. Spiny fruits 

 may be sometimes so large, as in the instance of Trapa natans, 

 that the question of adaptation to dispersal cannot be raised. 



The great variety of the modes of dispersal of seeds is in itself 

 an indication that the dispersing agencies avail themselves in 

 a hap-hazard fashion of characters and capacities that have been 

 developed in other connections. Seeds and fruits, having developed 

 certain characters under a particular set of life-conditions, on being 

 detached from the parent plant are brought into contact with con- 

 ditions quite outside their original environment. Qualities and 



