THE SEED'S FOOD-SUPPLY 135 



ance. When germination begins, these two large 

 leaves, swollen with nutritive matter, yield little by 

 little a part of their substance to the tiny plant and 

 suckle it, as it were. They might therefore be called 

 vegetable udders, nursing-leaves, but science calls 

 them cotyledons. The unhatched chick in its shell 

 has the yolk of the egg to furnish substance for its 

 growth, the young lamb has its mother's milk, the 

 germ of the plant has the juice of the cotyledons. 



' ' The same structure, with two cotyledons of great 

 size and easy to observe, may be found in the broad 

 bean, pea, kidney bean, and acorn, and in the stones 

 of the peach, apricot, and plum. It would also be 

 found in the pips of pears and apples as well as in 

 the seeds of most of our cultivated plants, but more 

 difficult to distinguish in proportion to the small- 

 ness of the seed. In every instance the seed would 

 be found to have two cotyledons as food-storehouses, 

 and also a gemmule and a radicle united by the ti- 

 gella. Other plants, on the contrary, like maize, 

 wheat, and the other cereals, as also the lily, tulip, 

 and iris, have but one cotyledon, one nursing-leaf 

 for the new vegetable organism. 



"It is not always easy, especially when the seed 

 is very small, to ascertain whether it has two coty- 

 ledons or only one; but as soon as germination has 

 begun, this difficulty disappears. Then the seed 

 with two cotyledons is seen to push up two leaves, 

 the very first to appear, situated opposite each other, 

 and very often differing in shape from those that 

 come later. In the radish, for example, they are 



