1907] How THE Seeds of Plants are Spread 31 



they will seldom drop seeds outside of such places, so that they 

 nearly always have something to climb. 



VI. Seeds that attract and are Spread by Birds. 



Who has not noticed the brilliantly colored berries on many 

 a shrub and tree? And who has not watched the birds eating 

 them? But ask the average person why the fruit is brightly 

 colored, and probably not one in twenty will give the correct 

 answer. Yet, as with the 'burs,' the reason is at once apparent. 

 Fruits of this nature are brightly colored to attract birds, and for 

 no other reason. This is also why so many berries remain on the 

 trees in winter time. The birds eat the fruit ; but the seeds are so 

 constructed that many of them are not damaged, and they are 

 eventually dropped where they have a chance of growing, in 

 most cases far remioved from their parents and brethren. In this 

 way the species is spread. This of course does not apply so 

 much to cultivated fruits, which have been altered and improved 

 by man. Strawberries, raspberries, cherries, mountain ash, and 

 practically all the other small berries that are brightly colored, 

 can be used as examples of this method of seed distribution. 

 Seeds are also carried by sticking to the muddy feet of birds and 

 animals. 



Many plants retain their seeds until the winter time, which 

 are then drifted along with the snow, in some cases several miles. 

 Small mammals and birds also carry many seeds to store them 

 up as food for winter use. Large nuinbers of these are lost and 

 if the situation is favourable thev grow. 



Many seeds are only partly developed for certain methods 

 of migration, and in some cases a few plants will be found to bear 

 two distinct forms of seeds. An example of this occurs in Rus- 

 sian pig-weed (Axyris aniarantoides) , some of the seeds of which 

 are winged while others are not. 



A number of aquatic plants and plants growing near water, 

 have seeds well adapted to water migration, the seeds or seed 

 capsule floating, and in still water are often drifted long distances 

 by the wind, or when in running water are carried along with 

 the current. A number of other seeds not specially adapted for 

 this purpose are also accidentally carried by running water, 

 . especially when there are floods. 



Many details and variations will be found by the Nature 

 student to supplement the above methods of migration among 

 seeds, the study of which should be a stimulus both to observa- 

 tion and deduction the faculties that Nature Study specially 

 aims at developing. 



