96 SEEDS AND SEEDLINGS. 



tabLe egg, and named the reserve material we now call 

 endosperm, albumen. It is now known to be something 

 very different, however, from the white of an egg. Fre- 

 quently it is starch, as we have seen in the corn, wheat, 

 oats, etc., or it may be an oil, as in the castor bean and 

 peanut, or something quite different from either. Hence, 

 modern botanists have renamed this substance endosperm, 

 a word meaning merely something contained "within the 

 seed," and therefore applicable to any kind of substance. 

 The old adjectives, albuminous and ex-albuminous, have 

 been retained for want of something better — ex-endo- 

 spermous being such an awkward compound that even 

 botanists hesitate to use it. 



By far the greater number of seeds are albuminous ; 

 that is, they consist of an embryo with more or less nour- 

 ishing matter stored about it in various ways. Even in 

 ex-albuminous seeds the endosperm is present ; it has 

 merely been absorbed and stored in the cotyledons before 

 germination. 



126. Principles of Classification. — We are now prepared 

 to understand the great fundamental distinctions upon 

 which botanists base their classification of Spermatophytes, 

 or seed-bearing plants. The first division depends upon 

 the presence or absence of a seed vessel, and ranges all 

 the higher plants into two classes according to this fea- 

 ture. The first division embraces the 



127. Gymnosperms, or naked-seeded plants, of which we 

 have had an example in the pine. They are the most 

 primitive type of seed-bearing plants and the most ancient. 

 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 with the 



128. Angiosperms, or plants that produce their seeds in 

 a special covering of closed carpels, like most of the fruits 



