SEEDS AND THEIR GERMINATION 207 



seeds has two similar parts? These two parts are called cotyledons. 

 What appears to be the use of these parts to the sprout? Consult 

 the results of Experiment 104. Note the root development in each 

 seed and the stem development. The sprouts get their food from the 

 seed. 



When we examined the different seeds in Experiment 

 105, we found that they each contained starch. When 

 the seeds were soaked and planted, we 

 found that a part of the seeds began to 

 grow, forming a sprout. This part is the 

 embryo already described. We also saw 

 that the bean seed divided into two 

 like parts which gradually withered and 

 shrank, as the sprout grew, while the 

 corn had only one such part. 



These parts are called cotyledons, or 

 seed leaves (Fig. 102). The bean seed 

 is a dicotyledon (two seed leaves) and 

 the corn a monocotyledon (one seed leaf). 

 These cotyledons are the food storehouses 

 for the germinating seed. As the sprout 

 grew, the root, with its root hairs, developed, and the 

 stem with its leaves. When these had grown strong 

 enough, the cotyledons, having performed their part, 

 dropped off. The plant was now ready to prepare its 

 own food by the aid of the sunlight. 



Experiment 107. Place several beans in a tumbler of damp saw- 

 dust and put it in a warm, light place. Keep the sawdust moistened. 

 After the beans are well sprouted, with a sharp knife cut one of the 

 half beans or cotyledons off from a sprout. Cut both cotyledons off 

 another sprout. Put the sprouts back on the sawdust. Do the 

 sprouts grow as well as those of the other beans ? 



Experiment 108. Fill a 16-ounce wide-mouth bottle about one 

 third full of peas or beans. Pour in water enough to more than cover 

 them. Tightly cork the bottle and put in a warm sunny place. Put 



