RELATION OF TEMPERATURE TO GERMINATION 19 



7. 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 gain an idea of the appearance of the parts, 

 since he is to study the germination of the pea in detail. 



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

 tion after the removal of the seed coats. 



8. Germination of the bean (or the white lupine), the pea, and the 

 grain of corn.* * Soak some beans or lupine seeds as directed in 

 Sec. 4, plant them, and make a series of sketches on the same 

 general plan as those in Principles^'Fig. 8. 



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

 the case of the corn, make six or more sketches at vai-ious stages 

 to illustrate the growth of the plumule and the formation of roots. 

 The student may be able to discover what becomes of the large 

 outer part of the embryo. This is believed to be the single coty- 

 ledon of the corn. It does not as a whole rise above ground, but 

 most of it remains in the buried grain, and acts as a digest- 

 ing 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. 



9. 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 modification of the parts. 



EXPERIMENT I* 



Relation of temperature to germination.* * Prepare at least four 

 beakers or tumblers, each with wet, soft paper packed in the 

 bottom to a depth of nearly an inch. Have a tightly fitting 

 cover, such as a square of window glass or a " clock glass," over 



* To THE Instructor : As some of the experiments upon seeds occupy a good 

 many days or weeks for their completion, the laboratory work should be pushed 

 on without waiting until these are finished. Results may be discussed from time 

 to time while the experiments are in progress and summed up when they are en- 

 tirely finished. 



