WHAT PLANTS DO FOR THEIR YOUNG. 159 



nut, the chestnut, the acorn, the lime-nut, the 

 almond, and the hickory-nut. In the Brazil nut 

 the seeds (which are what we commonly call the 

 nuts) are enclosed in a solid shell like that of a 

 coco-nut, and are themselves also hard and nut- 

 like. In the chestnut the fruit is a prickly cap- 

 sule, inside which lie the seeds, which we know 

 as chestnuts. 



But why have some plants so many seeds and 

 some so few ? Well, the simpler and earlier 

 types produce a very large number of ill-pro- 

 vided seeds, which they turn loose upon the 

 world to shift for themselves almost from the 

 outset. Many of them perish, but a few survive. 

 On the other hand, the more advanced plants, 

 as a rule, produce only a small number of seeds, 

 but each of these is well provided with starches 

 and oils for the growth of the young plant ; and 

 as most such survive, any tendency in the direc- 

 tion of laying by food-stuffs would of course be 

 favoured by natural selection. Just so among 

 animals, a codfish produces nearly a million eggs, 

 of which only two or three on an average survive 

 to maturity ; while a bird produces half a dozen 

 large and well-stored eggs, and a cow or a horse 

 rarely brings forth more than one calf or foal at 

 a birth. Decrease in the number of seeds is" a fair 

 rough test of relative progress. 



In nuts, you can see at once, the seeds are 

 very richly stored, and the young plant starts in 

 life, able to draw for a time on these ready-made 

 food-stuffs, until its green leaves are in a position 

 to lay by starches and protoplasm in plenty for 

 it. It draws by degrees upon the accumulated 

 materials. Such plants are like capitalists who 



