266 DECOMPOSITE ORGANS. CHAP. I. 



being the rudimenta of the future root, and gene- 

 rally denominated the radicle. 



Theradi- This conical and projecting process, which is 

 very evident in the Bean, has generally been re- 

 garded by botanists as being wholly a Radicle, and 

 accordingly described as such. But Mr. Knight has 

 shown, by the most satisfactory evidence, that it is, 

 externally at least, merely the part from which the 

 radicle proceeds, and not the radicle itself. And if 

 any one will take the trouble of examining the pro- 

 cess in the seed of the Horse-che*nut he may soon 

 satisfy himself of the fact, if he is at all dexterous 

 at dissection ; its external portion being merely a 

 prolongation of the lobes of the cotyledon, uniting 

 them together and investing not only the radicle 

 but the plumelet also. 



The radicle is the most constant of all the parts 

 of the seed, being often found, at least by means 

 of its integuments, where the plumelet is not at all 

 perceptible. Its most simple form is that of a 

 white point or speck upon the surface of the nucleus, 

 though it is also often to be found in the form of a 

 cylindrical or conical process, as already described. 

 Sometimes it is longer than the cotyledons, that is 

 as invested with its integuments, as in Rizophora ; 

 and sometimes it is shorter, as in leguminous plants. 

 It is generally, or rather almost universally, solitary, 

 except in the seeds of Secak, Triticum, and Hor- 

 deum, according to Gaertner. But the appearances 

 are certainly the same also in the genus Avena, 



