MATURATION OP THE FRUIT. 77 



101. Seeds are affected by all circumstances, that 

 affect the fruit, which indeed, as has been already 

 stated, appears to be created for their nutrition and 

 preservation. In. general, the fruit attracts organisa- 

 ble matter from the stem through the stalk, and the 

 seed from the fruit through, its placenta* ; and this 

 accounts, independently of other causes, for ,the 

 importance of the fruit to the seed. 



102. When the seed is ripe it is dry, all its free 

 water being parted with ; ; and its interior is occupied 

 by starch or fixed oil, or some other such substance, 

 together with earthy matters. It would, seem that, 

 so long as these secretions remain undecomposedj: so 

 long does the vitality of the seed continue unim- 

 paired $ and hence the great age at which certain 

 kinds of seeds have been found to grow. But, as it 

 is difficult to, prevent their decomposition, so is it 

 difficult to preserve seminal vitality for any consider- 

 able time ; and the difference found in the duration 

 of the growing powers of seeds probably depends 

 principally upon chemical differences in their consti- 

 tuent parts. Oily seeds, which readily decompose, 



* The placenta is a soft part of the inter, or of a frui^ upon which 

 the seed is formed. It is composed of thru-sided parenchyma, the 

 most absorbent of all the forms of tissue, and is in communication, 

 by its whole surface, with the parenchyma of the fruit 



f Not to speak of the doubtful instances of seeds taken from the 

 Pyramids having germinated, Melons have been known to grow at 

 the age of 40 years, Kidney beans at 100, Sensitive-Plant at 60, 

 Rye at 40 ; and there are now growing, in the garden of the Horti- 

 cultural Society, Raspberry plants raised from seeds 1600 or 1700 

 years old. (See Introduction to Botany, ed. S, p. 858.) 



