STORAGE OF FOOD EST THE SEED 



13 



15. Examination of the Four-o'clock Seed Examine the external 



surface of a seed i of the four-o'clock, and try the hardness of the 



outer coat by cutting it 



with it knife. From 

 seeds which have been 

 soaked in water at least 

 twent3--lour 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 section, 

 as seen with the mag- 

 nifying glass, to show 

 the parts, especially the 

 t\^"o cotyledons, lying 

 in close contact and 



4. Germinating Peas, growing in Water, 

 one deprived of its Cotyledons. 



encircling the white, starchy-looking endosperm." 



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

 other than the embryo.' "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 en^bryo, noting how it is 

 curved so as to enclose the endosperm 

 almost completely. 



16. Examination of the Kernel of Indian 

 Corn. — Soak .some grains of large yellow 

 field corn ' for about three davs. 



I n 



Fig. 5. Seeds with En- 

 dosperm, Longitudinal 

 Sections. 



I, asparagus (magnified) . 

 II, poppy (magnified). 



1 Strictly speaking, a fruit. 



2 Buckwheat 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. 



3 Reserve food derived from the part of the ovule (nucellus) jvist outside 

 of the embryo sac (Fig. 124) is called perispenn. 



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

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



