loo LETTER XXXV. 



shining, deep-browTi coat, a very broad sear {fig. 7. a.), 

 on one side, and a little conical elevation, which 

 touches with its point one edge of the scar (fig. 7. h.). 

 This conical elevation represents the position of the 

 radicle of the embryo that is hidden beneath the seed- 

 coat. Let the latter be removed ; you will find below it 

 a roundish, ^\Tinkled, fleshy body, which you cannot 

 separate into cotyledons, but whose radicle, curved down 

 upon itself, is distinctly visible. Here w^e have one 

 of several instances, where the cotyledons grow to 

 each other, so as not to be separable. The plumule, 

 or growing point, of this embryo lies closely packed 

 between the bases of the consolidated cotyledons, and 

 one wonders how it is to escape from them, when 

 the time shall arrive for the seed to commence its 

 growth into a plant. A simple alteration in the ad- 

 justment of the parts produces the desired effect. As 

 the cotyledons cannot unfold in the usual manner, 

 in order to allow the plumule to pass between them, 

 the passage of the latter upwards into the air is pro- 

 vided for by a slight extension of the bases of the 

 cotvledons, which begin to lenothen when the radicle 

 forces itself into the earth, and thus extricate the 

 plumule from what would otherwise be its prison- 

 house. 



The structure that exists in the Red and the Com- 

 mon Horse-chesnuts is nearly the same as what occurs 

 in the other species of the order, w^hich is an extremely 

 small one. The Pavias, or Scarlet Horse-chesnuts, 

 are the only others that deserve notice, and they are 

 so conformable in structure as not to require separate 



