90 



SEEDS AND SEEDLINGS 



4. Is there any nourishment in the embryos, apart from the endo- 

 sperm ? 



5. What is bran? 



6. Why will hogs fatten in a pine thicket in autumn? 



DICOTYLEDONS 



Material. — Dry and soaked seeds of the common bean, cotton, 

 and castor bean. Where cotton can not be obtained, okra, maple, ash, 

 morning-glory, or any other convenient specimens may be used, pro- 

 vided they are selected so as to show both the albuminous and the ex- 

 albuminous structure. Squash, pumpkin, horse-chestnut, etc., also 

 make good studies. Beans should be put to soak from 12 to 24 hours 

 before used ; cotton about 48 ; squash and pumpkin from 3 to 5 days, 

 and very hard seeds like the okra, castor bean, and morning-glory 

 from 7 to 10. If such seeds are clipped before soaking, that is, if a 

 small piece of the coat is chipped away from the end opposite the scar, 

 they will soften more quickly. Keep them in a warm place with an 

 even temperature till just before they begin to sprout, when the con- 

 tents become softened. Very brittle cotyledons may be softened quickly 

 by boiling them for a few minutes. 



121. Examination of Some Typical Seeds. — Take a bean 

 from the pod, noticing carefully its point of attachment. 

 Lay it on one side and sketch it, then turn it over and 

 draw the narrow edge that was attached to the pod. 

 Notice the rather large scar (commonly called the eye of 

 the bean) where it broke away from 

 the point of attachment. Label this 

 in your drawing, hilum. Just below 

 the hilum, look for a minute round 

 pore like a pin hole. Label this 

 micropyle. Compare a soaked bean 

 with a dry one ; what difference do 

 you perceive .? How do you account 

 205, side view; 206, rhaphai for the change in size and hardness ■" 

 '^ic^p'y'r'"^ '■ '"""■ "■ Fi"dth6 hilum and the micropyle in 

 the soaked bean. Make a section 

 through the long diameter at right angles to the flat sides, 

 press it sHghtly open and sketch it. Notice the hne or 

 slit that seems to cut the section in half longitudinally, and 



206 



205, 206, — A kidney bean : 



