184 LESSONS IX AGRICULTURE 



horny gluten, and germ have been removed, there re- 

 mains only starch, of which there are two kinds the 

 horny starch and the white starch. The horny starch 

 lies at the back and sides of the kernel. The white starch 

 is at the crown end of the kernel above the germ, and 

 nearly surrounds the germ toward the tip of the kernel. 

 Separate as far as possible the horny starch and the 

 white starch. Make an enlarged drawing of the front 

 view of a grain of corn, showing and naming the parts. 



NOTE. All seeds except the seeds of conifers, are of 

 one of these two types. In the bean, there are two 

 cotyledons, and the food material of the seed is stored in 

 these cotyledons. 



In the corn there is only one cotyledon, and the 

 food material is stored outside of the embryo, in a part 

 called the endosperm. 



3. Study of a Grain of Wheat 



Soak a few grains of wheat in warm water. With a 

 sharp knife try to remove the covering of the grain. 

 There are four of these coverings on a grain of wheat, 

 three epidermic layers and one testa or true seed coat. 

 These coats constitute the bran and make up about 11% 

 of the grain. Immediately under the testa is the en- 

 dosperm. This makes up a large part of the seed and is 

 the flour of commerce. Note the position, form, and 

 size of the embryo. Make a diagram representing a 

 cross section of a grain of wheat, showing all these parts. 



NOTE TO TEACHERS. Send for "School Set of Eco- 

 nomic Seeds," to Edgar Brown, Seed Laboratory, De- 

 partment of Agriculture, Washington, D. C. 



