348 



ELEMENTARY STUDIES IN BOTANY 



FIG. 20. The "sawdust box" for testing 

 corn : explained in text. After Iowa 

 State College Bulletin. 



surface is laid a strong white cloth ruled in numbered squares 

 with sides two or three inches long. This cloth is held in 



place by being tacked to the 

 box. As many ears of corn 

 can be tested as there are 

 squares on the cloth, and 

 each ear must bear a number 

 corresponding to a numbered 

 square. From each ear six 

 kernels are removed : one 

 from near the base of the ear, 

 one from the middle, and one 

 from near the tip, and three 

 others in the corresponding 

 positions on the opposite side of the ear. These six kernels, 

 selected as samples of the entire ear, are placed upon the 

 square of cloth whose number corresponds to that of the ear. 

 When all the kernels to be tested have been placed in 

 their proper positions on the cloth, another cloth is laid over 

 them and sprinkled. Then another 

 cloth, larger than the box, is placed 

 upon the sprinkled cloth, shaped as a 

 lining to the box, and covered with two 

 inches of moist and pressed-down saw- 

 dust, over which the edges of the large 

 cloth are folded (Fig. 20). If kept in 

 a warm place, the grains will germinate 

 in about six days, when the cover is 

 removed carefully so as not to displace 

 them. The condition for examination 

 is when shoots (stems) are about two 

 inches long, and if it is discovered that 

 the grains have been uncovered too 

 soon, the covering should be replaced. Each ear is repre- 

 sented by six kernels, and if one or more of the kernels have 



FIG. 21. Section of a grain 

 of corn : explained in the 

 text. After FRANK. 



