246 ANATOMY AND PHYSIOLOGY OK PLANTS. 



of a lobe of the recent bean; and it is easily seen in a thin slice of 

 almost any mature seed, if it be held up to the light after it has been 

 soaked in water. 



40. The use of the cotyledon is, to supply the plume 

 with nourishment until its root is sufficient to support 

 it by nourishment from the earth. 



Accordingly we find, upon planting, for instance, a dicotyledonous 

 seed, as the lupin, that after some days it will protrude above the 

 ground in the form of two thick, orbicular fleshy leaves. These, 

 before the seed germinates, composed its two sides or cotyledons ; 

 the juices they contain in this leaf-like state, go to the nourishment 

 of the young plant, and by the time that they are exhausted and 

 dead, the root is strong enough to depend on its own exertions 

 for support. 



41. The radicle or rostellum, is by far the most con- 

 stant part, not only of the embryo, but of the whole 

 kernel, for it is to be found in those seeds which have 

 no other vestige of the embryo. 



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. 



42. The plume or plumelet is so called, from its re- 

 sembling, in some examples, a small feather issuing by 

 a small stem immediately from the radicle; in other 

 words, it is the first bud of the new plant. 



In plants which possess but one cotyledon, it is very generally 

 wanting, and even in those having two lobes, it is not nnfrequently 

 absent. In most of the latter sort of seeds, however, the plume is 

 met with placed on the top of the radicle, lying between the coty- 

 ledons, by which it is variously compressed and folded on itself. 



43. We ha\e now described the different organs of 



