STOKAGE OF NOURISHMENT IN THE SEED. 19 



gathered from the air and water, but most of it, during the 

 very early life of the plant, is due to the reserye material 

 stored in the seed. 



Any one who has watched the slow growth of seedling grass 

 plants and the very rapid growth of young corn plants can 

 appreciate the effect of an abundant supply of food in the seed 

 in securing a rapid start for the seedling. This particular 

 illustration is a good one, since corn is itself a kind of grass. 



25. Storage -of Nourishment outside of the Embryo. — In 

 very many cases the cotyledons contain little nutriment, but 

 there is a supply of it stored in the seed 



beside or around them, Figs. 1 and 8. 



26. Examination of the Four-o^dock Seed; 

 its Germination. — Examine the external sur- 

 face of a seed.1 of the four-o'clock, and try 

 the hardness of the outer coat by cutting , it 

 with a knife. Prom seeds which have been ^ „ 



soaked in water at least 24 hours peel off the -r^ „ , ,. 



^ Fig. '8. — Albuminous 



coatings and sketch the kernel. Make a cross- seeda, Longitudinal Seo- 

 section of one of the soaked seeds which has not tions. 

 been stripped of its coat^gs, and sketch the sec- i_ asparagus (magnified), 

 tion as seen with the magnifying glass, to show II, poppy (magnified), 

 the parts, especially the two cotyledons, lying 

 in close contact and encircling the white starchy-looking endosperm.^ 



The name endosperm is applied to nourishment 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 embryo, noting how 

 it is curved so as to inclose the endosperm almost completely. 



Sketch the germinating seed and the young seedling at two or three 

 stages of its growth to show the form and development of the cotyledons, 

 and try to find out whether the endosperm disappears. 



27. Examination of the Kernel of Indian Corn; its Germination. — 

 Soak some grains of large yellow field-corn' for about three days. 



* Strictly speaking a fruit. 



2 Buckwheat furnislies another excellent study in s^eds -wiih endosperm. Like 

 tliat of the four-o'clock it is, strictly speaking, a fruit. 



« The varieties with long flat kernels, raised in the Midiile and Southern States 

 under the name of " dent com," are the best. 



