SECT. it. VEGETATION; 5 



rotting, and we find that almost every sort of seed, 

 by means of these coverings, must remain different 

 lengths of time in the earth, before they begin to 

 germinate. Some will not spring in tire natural 

 ground till the second year after they are buried, 

 while others will begin to shoot in three days after 

 sowing. This appears owing to their requiring dif- 

 ferent degrees of moisture, heat and air, to make 

 them germinate ; i. e. bring them into a state of 

 fermentation. 



The substance of see,ds Appears to be spent first in 

 feeding the radicle, and then in the nourishment of 

 the two first, or seed leaves, which are commonly of 

 a different size, shape and substance from the proper 

 leaves of the plant : From between these comes * 

 shoot bearing the true leaves. The lobes (or substance) 

 of seed consist of a farinous nutriment, adapted to 

 the infant state of the plant when softened and disr 

 solved by the moistgre of the earth, which extends 

 and unfolds the young plant (or plumule) in the 

 same manner, as the nourishing juice in the eggs of 

 animals hatches their embryo. The seed-leaves, 

 therefore, contain a sugary juice, which is evident 

 from insects so greedily biting them, and their plea- 

 sant taste in sal lads, as those of turnips, cabbages^ 

 &c. They are thick and succulent, calculated to 

 imbibe air and moisture from the atmosphere, for 

 the support of the tender plant, that might otherwise 

 suffer by drought : for it must proceed in growth, or 

 ft would quickly die. When the radicle has struck 

 downwards, the office of the seed is evidently to 

 nourish these leaves, as is seen by the seed coming 

 above the ground with them, exhausted of its sub- 

 Stance a mere shell sticking to the top of the 

 leaves. 



But some plants haye no seed-leaves properly so 



