NATURE OF SEEDS. 277 



store of starch, and sugar and other soluble princi- 

 ples are formed. For this reason all kinds of tubers, 

 such as potatoes, for example, become sweet as soon 

 as the ejes or buds begin to grow: it is an effect 

 similar to the malting of grain. 



726. The embryo of a seed possesses vitality, but 

 has no power, at first, of assimilating the elements of 

 organic matter directly from the air ; it is, therefore, 

 able to convert starch, gluten, and other proximate 

 principles, into organized matter, and consequently 

 grows and increases in size, by feeding on the store 

 of organic matter prepared for its use in the seed. 



727. The means provided to insure the reproduc- 

 tion of plants, are very various. In some plants, 

 seed only is formed ; whilst in others we observe 

 tubers or collections of food, prepared and preserved 

 in underground receptacles, for the nourishment of 

 the yonng plants of the next season. 



728. Many plants, such as wheat, barley, beans, 

 &c., form seeds which consist merely of an embryo, 

 or growing body, surrounded with a supply of organic 

 food suflBcient for the use of the young plant, until 

 it has grown large enough to feed itself. The seeds 

 of other plants are more complete, being surrounded 

 with an additional quantity of organic matter, which, 

 by decaying, insures to the roots and leaves of the 

 young plant, a due supply of gaseous food as soon as 

 it is able to feed itself by those organs. 



729. The seeds of all plants which bear fruit, are 

 of this kind. When a peach, for example, falls from 



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