2 86 . TEXTBOOK OF BOTANY 



stone ; the soft part inside the stone is the seed, and the seed 

 coat is thin and soft. Some fruit coats, Hke those of the 

 chestnut and the gooseberry, bear spines that protect them, 

 especially while they are young and growing, from the 

 attacks of animals. 



292. How Fruits Help in the Scattering of Seeds. — A 

 great many of the structures of both seeds and fruits are help- 

 ful to the plant because they bring about, in one way or 

 another, a scattering of its seeds. Plainly it is a good thing 

 for a species to have its seeds scattered so that it may spread 

 over a wider area, provided enough seeds are formed. The 

 more widely the seeds are scattered, the more there are 

 that will fall in places where that particular kind of plant 

 cannot grow ; and unless a great many seeds are pro- 

 duced, so that a goodly number may still fall in favorable 

 places, a wide distribution may be bad rather than good for 

 the species. There are plants, such as the oak, the walnut, 

 and the hickory, that have no particular means for distribut- 

 ing their seeds. The fruits or seeds of such plants simply 

 fall to the ground under the plant that bore them ; they are 

 not scattered, except as they may be accidentally blown or 

 rolled or knocked about for short distances. Of the plants 

 whose seeds are more widely scattered, a good many depend 

 upon the wind for this purpose. Sometimes the seeds alone 

 are carried by the wind ; but often the whole fruit is blown 

 about. Fruits that are distributed in this way are nearly 

 always small and light, and being small they are usually one- 

 seeded fruits. Some, like the fruits of the maple and the elm, 

 have wing-like attachments that increase their chances of 

 being blown about. Many of the fruits of the composite 

 family, such as those of the thistle and the dandelion, bear 

 what looks like a tuft of hairs or bristles ; these bristles are 

 really the sepals of the flower, which have remained attached 

 to the fruit. 



Currents of water also play a large part in the scattering of 



