MONOCOTYLEDONS ONION 5.7 



part of the embryo itself while in the Castor-seed 

 it is outside the embryo, and must be absorbed by 

 the cotyledons. 



6. Now examine the Onion seedling. Here again 

 is a green arch which pushes up through the soil, 

 and coming up above the surface gradually pulls 

 one end out of the seed (to which however it 

 remains attached for some time), while the other end 

 fixes itself in the ground by roots. Then it stands 

 upright a thin cylindrical green organ, without petiole 

 or blade, but. with quite low down on it, a tiny 

 white scale. This scale turns out to be the beginning 

 of a leaf, and other leaves follow, narrow and with- 

 out difference of stalk and blade, and thereby quite 

 unlike the broad stalked leaves of the other seedlings 

 we have studied, but still in every sense of the word 

 leaves. They all arise from about the same place, 

 the stem, so far as there is one, appears to begin 

 and end at this spot. It is indeed very short almost 

 entirely absent. What then is the green curved body 

 that came first out of the seed ? 



Its likeness to the ordinary leaves of the mature 

 Onion plant points to its being of a leaf -nature, 

 and just as in the Castor, the two cotyledons, obvi- 

 ously the first leaves, remain for some time with at 

 least their tips inside the seed coat, and in intimate 

 contact with the endosperm which they gradually 

 absorb, so here in the Onion the first leaf is con- 

 nected by its tip with the seed and absorbs nourish- 

 ment from it, and must in the same way be called 

 a cotyledon. But there is this difference, the Onion 

 has only one cotyledon, not two, nor is there in it 



