SEEDLINGS. 



311 



the stem arches up its back in this way it pries with the cotyledons against 

 the upper seed coat, but tlie lower seed coat is caught against this heel, and 

 the two are pulled gradually apart. In this way 

 the embryo plant pulls itself out from between 

 the seed coats. In the case of seed which are 

 planted deeply in the soil we do not see this con- 

 trivance unless we dig down into the earth. The 

 stem of the seedling arches through the soil, pull- 

 ing the cotyledons up at one end. Then it 

 straightens up, the green cotyledons part, and 

 open out their inner faces to the sunlight, as 

 shown in fig. 406. If we dig into the soil we 

 shall see that this 

 same heel is formed 

 on the stem, and 

 that the seed coats 

 are cast oft' into the 

 soil. 



Fig. 406. 

 Pumpkin seedling rising from the ground. 



Arissema triphyllum. 



588. Germination of seeds of jack-in-the-pulpit. — The ovaries of jack-in- 

 the-pulpit form large, bright red berries with a soft pulp enclosing one to 



Fig. 407. 

 Seedlings of iack-in-the-pul- 

 pit \ embryo backing out of the 

 seed. 



Fig. 408. 

 Section of germinating embryos of 

 iack-in-the-pulpit, showing young 

 leaves inside the petiole of the coty- 

 ledon. At the left cotyledon shown 

 surrounded by the endosperm in the 

 seed ; at right endosperm removed to 

 show the club-shaped cotyledon. 



several large seeds. The seeds are oval in form. Their germination is inter- 

 esting, and illustrates one type of germination of seeds common among 



