8 FOUNDATIONS OF BOTANY 



Note the cavity in each cotyledon caused by the pressure of the 

 plumule and of the hypocotyl. 



4.^ Examination of the Pea. There are no very important points 

 of difference between the bean and pea, so far as the structure of 

 the seed is concerned, but the student should rapidly dissect a few- 

 soaked peas to get an idea of the appearance of the parts, since he 

 is to study the germination of peas in some detail. 



Make only one sketch, that of the hypocotyl as seen in position 

 after the removal of the seed-coats. 1 



5. Germination of the Bean or the White Lupine, the Pea, and the 

 Grain of Corn. Soak some beans or lupine seeds as directed in 

 Section 3, plant them, 2 and make a series of sketches on the same 

 general plan as those in Fig. 9. 



Follow the same directions with some peas and some corn. In the 

 case of the corn, make six or more sketches at various stages to illus- 

 trate the growth of the plumule and the formation of roots ; first a 

 main root from the base of the hypocotyl, then others more slender 

 from the same region, and later on still others from points higher 

 up on the stem (see Fig. 15). The student may be able to dis- 

 cover what becomes of the large outer part of the embryo. This is 

 really the single cotyledon of the corn (Fig. 6). It does not as a 

 whole rise above ground, but most of it remains in the buried grain, 

 and acts as a digesting and absorbing organ through which the 

 endosperm, or food stored outside of the embryo is transferred into 

 the growing plant, as fast as it can be made liquid for that purpose. 



6. Germination of the Horse-Chestnut . Plant some seeds of the 

 horse-chestnut or the buckeye, study their mode of germination, and 

 observe the nature and peculiar modifications of the parts. 



Consult Gray's Structural Botany, Vol. I, pp. 19, 20. 



/ 7. Conditions Requisite for Germination. When we 

 try to enumerate the external conditions which can affect 



1 The teacher will find excellent sketches of most of the germinating seeds 

 described in the present chapter in Miss Newell's Outlines of Lessons in 

 Botany, Part I. 



2 The pupil may economize space by planting the new seeds in boxes 

 from which part of the earlier planted seeds have been dug up for use in 

 sketching, etc. 



