12 PRACTICAL COURSE IN BOTANY 



grains of com; then pour in water till the bottle is full. Tie a piece of 

 wire-netting or stout sackcloth over the top to keep the seeds from being 

 forced out. Bind both the neck and the body of the Ijottle tightly with 

 strong cords encircling it in both a horizontal and vertical direction, and 

 place under water in a moderately warm temperature. Watch for results. 

 Experiment 16. Is the force exerted in the last experiment 

 A merely mechanical one, like the bursting of a water pipe, or 



IS IT PHYSIOLOGICAL AND THUS DEPENDENT ON THE FACT THAT THE 



SEEDS ARE ALIVE ? — To auswcr this question try Exp. 15 with seeds 

 that have been killed by heat or by soaking in formalin. 



Practical Questions 



1. Will a pound of pop corn weigh as much after being popped as be- 

 fore? (Exp. 10.) 



2. What causes the difference, if there is any? (Exp. 10.) 



3. Does the tuft of downy hairs at the tip of wheat and oat grains 

 influence their water supply ? The spongy covering of black walnuts and 

 almonds? The pithy inside layers of pecans and English walnuts? 

 (Exps. 12, 13.) 



4. Why will seeds, as a general thing, germinate more readily after 

 being soaked? (Exps. 11, 14, 16.) 



III. TYPES OF SEEDS 



Material. — Dry and soaked grains of corn, wheat, or oats ; bean, 

 squash, castor bean, and pine seed, or any equivalent specimens showing 

 the differences as to number of cotyledons and the presence or absence of 

 endosperm. Each student should be provided with several specimens, 

 both soaked and dry, of the kind under consideration. Corn, beans, and 

 wheat need to be soaked from 12 to 24 hours ; squash and pumpkin from 

 2 to 5 days, and very hard seeds, like the castor bean and morning-glory, 

 from 5 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, or eye, 

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

 temperature till just before they begin to sprout, when the contents become 

 softened. Very brittle cotyledons may be softened quickly by boiling 

 for a few minutes. 



No appliances are needed beyond the pupil's individual outfit and some 

 of the food tests given in Section I of this chapter. 



II. Dissection of a grain of corn. — Examine a dry grain 

 of corn on both faces. Wliat differences do yon notice? 

 Sketch the grooved side, labeUng the hard, yellowish outer 



