17-J 



MORE ABOUT STARTING NEW PLANTS 



119. Seeds and Embryos. Two common types of seed 

 are represented by the bean and the corn. 



a. A bean seed can easily be split into two equal parts, 

 called cotyledons. Attached to one end of the seed, 

 between the cotyledons, are a pair of miniature leaves 

 called the plumule, and a short root sprout known as the 



radicle. The three 

 parts together form the 

 embryo. This contains 

 the germ plasm that was 

 formed by the union of 

 pollen and ovules. 



Plants whose leaves 

 are net-veined and 

 which bear flowers hav- 



POOR ALFALFA SEED. 

 Before testing. 



divisions to their calyx 

 and corolla produce 

 seeds of the bean type. 

 b. A grain of corn 

 cannot readily be split 

 apart into halves. A 

 cross section of the ker- 

 nels, especially if the 

 seed has been soaked 

 in water, will show the embryo at the base. This embryo 

 or germ consists of one irregular cotyledon, a plumule 

 made of sheathing leaves, and a radicle. Occupying 

 the broad end of the grain is the endosperm, a mate- 

 rial that is mostly starch, to feed the embryo when it 

 sprouts. 



This corn type of seed is found in plants that have 

 parallel-veined leaves and that bear flowers with the parts 

 commonly arranged by threes or by sixes. 



