CHAP. V. FUNCTION OF REPRODUCTION. 273 



other may be seen in a withered state attached to 

 the inner edge of one suture of the stone, whilst the 

 perfect seed is attached to the other. 



(271.) Maturation of the Fruit. Whilst the fruit 

 continues to swell, the sap is drawn with increased 

 energy towards those branches on which it hangs, and 

 a rapid exhaustion takes place of the nutritious materials 

 previously deposited in the stem. As these materials 

 are distributed among the whole of the fruit, the ad- 

 vantage of thinning it early is evident, as the share 

 which each will receive must be proportionably in- 

 creased. We may compare the maturation of the fruit 

 to the period of gestation in animals ; and it is of very 

 varied duration in different species. The greater num- 

 ber of plants ripen their fruit considerably within a 

 year from the time when the flowers first expand, and 

 some require only a few days for this purpose. But 

 there are certain trees, as some oaks, which require 

 eighteen months ; and the fruit of the juniper, and the 

 cones of many of the fir tribe, hang above a twelve- 

 month. The cedar requires twenty-seven months to 

 bring its seed to perfection. 



The following list contains a few other examples of 

 the different periods required by some plants for the 

 maturation of their seeds : 



Days 13. Panicum viride. 



14. Avena pratensis. 



16 30. Most other Gramineae. 



Months 2. Raspberry, Strawberry, Cherry, Elm, 

 Poppy, &c. 



3. Bird -cherry, Lime, Reseda-luteola. 



4. Whitethorn, Horse-chestnut. 



5 6. Vine, Pear, Apple, Walnut, Beech. 



7. Olive. 



8 9- Colchicum autumnale, Missletoe. 



1011. Most Fir trees. 



No uncombined water is found in the seed when it is 

 completely ripe ; but it is now chemically united in 



