12 THE OAK. 



ripening of the former. At the more pointed free end 

 of the acorn is a queer little knob, which is hard and 

 dry, and represents the mummified remains of what was 

 the stigma of the flower, and which lost its importance 

 several months previously, after receiving the pollen. 



The outer hard coat of the acorn is a tough, leather- 

 brown polished skin, with fine longitudinal lines on it, 

 and it forms the outer portion of the true covering of 

 the fruit, called the pericarp (Fig. 2, p). On removing 

 it we find a thin, papery membrane inside, adhering 

 partly to the above coat and partly to the seed inside. 

 This thin, shriveled, papery membrane is the inner part 

 of the pericarp, and the details of structure to be found 

 in these layers may be passed over for the present with 

 the remark that they are no longer living structures, 

 but exist simply as protective coverings for the seed 

 inside. 



The centre of the acorn is occupied more or less 

 entirely by a hard brown body the seed which usual- 

 ly rattles about loosely on shaking the ripe fruit, but 

 which was previously attached definitely at the broad 

 end. A similar series of changes to those which brought 

 about the separation of the acorn from the cup name- 

 ly, the shriveling up of the tiny connecting cords, 

 etc. also caused the separation of the seed from the 

 pericarp, and we may regard the former as a distinct 

 body. 



Its shape is nearly the same as that of the acorn in 

 which it loosely fits, and it is usually closely covered 



