16 



FOUNDATIONS OF BOTANY 



the outer coat by cutting it with a knife. From seeds which have 

 been soaked in water at least twenty-four hours peel off the coatings 

 and sketch the kernel. Make a cross-section of one of the soaked 

 seeds which has not been stripped of its coatings, and sketch the sec- 

 tion as seen with the magnifying glass, to show the parts, especially 

 the two cotyledons, lying in close contact and encircling the white, 

 starchy-looking endosperm. 1 



The name endosperm is applied to food stored in parts of the 

 seed other than the embryo. 2 With a mounted needle pick out the 

 little almost spherical mass of endosperm from inside the cotyledons 

 of a seed which has been deprived of 

 its coats, and sketch the embryo, noting 

 how it is curved so as to enclose the 

 endosperm almost completely. 



19. Examination of the Kernel of In- 

 dian Corn. Soak some grains of large 

 yellow field corn 3 for about three days. 



Sketch an unsoaked kernel, so as to 

 show the grooved side, where the germ 

 lies. Observe how this groove has be- 

 come partially filled up in the soaked 



FIG. 6. Lengthwise Section of kernels. 



Grain of Corn. (Magnified Remove the thin, tough skin from 

 about three times.) 



y ,yellow,oilypartof endosperm; one of flatter, and notice its transpar- 



w, white, starchy part of en- ency. This skin the bran of unsifted 



dosperm ; p, plumule ; s, the com meal _ doeg not exac tly correspond 



shield (cotyledon), in contact . . . ,. 



with the endosperm f or absorp- to the testa and inner coat of ordinary 



tion of food from it ; r, the seeds, since the kernel of corn, like all 

 primary root. Qther graing (and Uke the geed of the 



four-o'clock), represents not merely the seed, but also the seed-vessel 

 in which it was formed and grew, and is therefore a fruit. 



1 Buck wheat furnishes another excellent study in seeds with endosperm. 

 Like that of the four-o'clock, it is, strictly speaking, a fruit ; so also is a grain 

 of corn. 



2 In the squash seed the green layer which covered the embryo represents 

 the remains of the endosperm. 



3 The varieties with long, flat kernels, raised in the Middle and Southern 

 States under the name of " dent corn," are the best. 



