17 



3. What is the general name for a dehiscent fruit? What is the 

 pericarp? 



4 Group the dehiscent forms into (1) those derived from a simple 

 one-celled ovary, and (2) those derived from a compound several-celled 

 ovary. 



5. Examine the indehiscent fruits ; determine how they have develop- 

 ed from the ovary, and make out the changes that have taken place while 

 maturing. 



6. Group the fleshy fruits itito (1) berries, drupes, pomes, hips, 

 haws, and pepos. 



7. Study the fruits of the evergreens ; compare them. 



8. Study the fruits of the ferns, club-mosses, and mosses. 



9. Account for the brilliant colors of some of the fruits, 



10. Why is unripe fruit usually green? 



11. Why are the seeds of many fruits unpleasant to the taste? 



12. Why have some fruits a hard coat next the seed? 



13. Why are the seeds of some fruits very small? 



14. Why are the edible portions of nuts protected by a shell, and 

 unprotected in berries and such fruits? 



XXVI. Nuts. 



Collect specimens of hazelnuts, beech nuts, chestnuts, hickory nuts, 

 walnuts, and butternuts. 



1. Are all of these fruits? Why? Are they dehiscent or indehiscent? 

 Why? 



2. In the case of the first three, of what is the "bur" composed? 

 Does it dehisce in all three? 



3. In the case of the last three, of what is the "shuck" or "hull" 

 composed? Does it dehisce in all three? 



4. How many cells and seeds does each nut contain? In the chest- 

 nut, for example, there are sometimes two kernels in a nut. Explain. 



5. What change has" taken place in the wall of the ovary of each 

 nut in the process of ripening? 



6. Give a botanical definition of nut. Is the acorn a nut? Is the 

 horse-chestnut a nut? 



7. Why are nuts usually dull colored? 



8. Why is the edible portion of nuts protected by a shell ? 



9. How are the nuts distinguished? 



10. How are unripe nuts protected while on the tree? 



M. Study the common commercial nuts, such as are sold on the 

 market. 



■2 BULL. 142 



