CHAPTER XX 
ECOLOGY OF FRUITS; DISPERSAL OF FRUITS AND SEEDS 
234. Subjects of the Chapter. — The ecology of fruits and 
seeds is concerned mainly with the various means by which 
seeds are protected from decay or from being destroyed by 
animals, and the methods by which they are enabled to 
secure transportation and to become planted in localities 
suitable for their growth. The latter topic, that of seed 
distribution, is the one which will be discussed in this 
chapter. 
235. Dispersal of Seeds. — Seeds are not infrequently 
scattered by apparatus by which the plant throws them 
about. More commonly, however, they depend upon other 
agencies, such as wind, water, or animals, to carry them. 
Sometimes the transportation of seeds is due to the struc- 
ture of the seeds themselves, sometimes to that of the 
fruit in which they are enclosed; the essential point is to 
have transportation to a leng distance made as certain as 
possible, to avoid overcrowding. 
236. Explosive Fruits.—Some dry fruits burst open 
when ripe in such a way as to throw their seeds violently 
about. Interesting studies may. be made, in the proper 
season, of the fruits of the common blue violet, the 
pansy, the wild balsam, the garden balsam, the cranes- 
bill, the herb Robert, the witch-hazel, the Jersey tea, and 
some other common plants. The capsule of the tropical 
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