THE FLOWERING PLANT SEEDS 337 



I. Size. — "What is the length ? Breadth ? Thickness? 

 Measure several carefully. What variations in 

 size ? 



c. Color. — "What is it? "What variations? Is the 



color in the covering or in the fleshy portion? 

 Of what use is the color? "What is the cause 

 of it? 



d. Structure. 



1. The seed-coat or testa. — "What is its structure ? 



Color? Use? 



2. The liiluin, or scar left by the seed-stalk or funi- 



culus. — "What is its position? Shape? Size? 

 Use? 



Near the hilum find 



3. The micropyle. — Examine several seeds to see 



if its position is constant. "What is its shape ? 

 Size? Use? 

 Tear away the testa and note 



4. The cotyledons. — How many are there? "What 



is their position ? Shape ? Color ? "What re- 

 lations do they bear to the embryo as regards 

 position and size ? 



5. The embryo, consisting of caulicle and plu- 



mule. — "What is its shape ? Is it attached to 

 the cotyledons? If so, how? How do you 

 distinguish the caulicle from the plumule ? In 

 what direction does the tip of the caulicle 

 point ? Examine several beans to see if it al- 

 ways points in this direction. "What is the posi- 

 tion of the tip of the caulicle with relation to the 

 micropyle ? "What is the structure of the cauli- 

 cle? Shape? Size? What is the position of the 

 plumule ? Of what is it composed ? Compare 

 33 



