20 



EXPERIMENTS WITH PLANTS 



draws it through), it would seem advisable to have as 

 much contact as possible. Some seeds have the cover 

 closely applied to the germ so as to be in contact 

 everywhere; others (Peanut, Filbert, etc.), wiiere the 

 seed-contents are loose inside the cover, have a small 

 amount of contact; investigate this point in as many 

 seeds as you can. In some seeds the cover separates 

 in places from the germ when the seed is placed in 

 water, so that the amount of contact is diminished; 

 subsequently the cover becomes closely stretched over 

 the germ ; in what seeds does this happen ? 



It would seem that the portion of the germ which 

 is in immediate contact with the opening must receive 

 water more quickly and in larger quantities than other 

 parts more remote. Do you usually find the caulicle 



near the opening?^ Does the 

 caulicle usually swell and grow 

 more quickly than other por- 

 tions of the seed ? Do you 

 consider its position advanta- 

 geous ? Notice the pocket 

 around the caulicle in the 

 Beans (Fig. 22), Pea, Buckeye 

 (Fig. 46), etc. Do you think 

 this might help to draw up 

 water (by capillarity) and retain it, so keeping the 

 caulicle moist? 



22 



Scarlet Runner Bean opened, 

 showing tlie pocket into which 

 the caulicle fits. 



1 Examine particularly the Peach, Plum, Cherry, Walnut, Pecan, etc. 



