20 PRACTICAL COURSE m BOTANY 



matter stored about it. Even in seeds which appear to 

 have none, the endosperm is present at some period during 

 development, but is absorbed by the cotyledons before ger- 

 mination, 



17. Manner of storing nourishment. — In the various seeds 

 examined, we have seen that the nourishment for the young 

 plant is either stored in the embryo itself, as in the coty- 

 ledons of the bean, acorn, squash, etc., or packed about them 

 in the form of endosperm, as in the corn, wheat, and castor 

 bean. 



18. The nimiber of cotyledons. — Seeds are also classed 

 according to the number of their cotyledons, as having one 

 two, or many cotyledons. The first two kinds make up the 

 great class of Angiosperms, which includes all the true flower- 

 ing plants and forms the most important part of the vegeta- 

 tion of the globe. The last is characteristic of the great 

 natural division of Gymnosperms, or naked-seeded plants, 

 of which we have had an example in the pine. They are the 

 most primitive type of living seed-bearing plants. Though 

 they are not so abundant now as in past ages, numbering 

 only about four hundred known species, they present many 

 diversities of form, which seem to ally them on the one hand 

 with the lower, or spore-bearing plants (ferns, mosses, etc.), 

 and on the other hand with the Angiosperms. 



Practical Questions 



1. Make a list of all the seeds you can find that have verj'^ thick coty- 

 ledons, and underline those that are used as food by man or beast. 



2. Make a similar list of all the kinds with thin cotyledons and more or 

 less endosperm, that are used for food or other purposes. 



3. Do you find a greater number of foodstuffs among the one kind 

 than the other ? 



4. How do the two kinds compare, as a general thing, in size and 

 weight ? 



5. From what part of the castor bean do we get oil ? of the peanut ? 

 of cotton seed? (Exps. 1-6.) 



6. Is there any valid objection to the wholesomeness of peanut oil, and 

 of cottonseed lard as compared with hog's lard ? (1, 3.) 



