FKUITS. 95 



obtain a general conception of the structure and cycle of 

 development of flowering plants, but if we were to take a 

 single seed, and watch its germination and every detail of 

 its subsequent life and growth, we should find its develop- 

 mental history a connected synopsis of what we have 

 learned from so many sources. This may be stated briefly 

 as follows : In the spermaphytes, or higher plants, the 

 embryo arises from a single cell, the oosphere, contained 

 in the embryo-sac. The embryo has all the essential vege- 

 tative parts of the mature plant, and in germination these 

 are unfolded, finally developing into root, stem, and leaf. 

 Certain buds of the plant in this later stage of its develop- 

 ment become ordinary branches, while others undergo ex- 

 traordinary modifications and become reproductive branches 

 or flowers. In due course of time the oosphere is formed 

 in the embryo-sac of the various ovules, and after fertiliza- 

 tion the same history is repeated in a; subsequent genera- 

 tion. Plants lower in. the scale of life exhibit similar, 

 though not identical, phases of developmental history. 

 We shall study these next and then pass to the subject of 

 relationships exhibited by the higher plants. 



In connection with the preceding exercises it is desirable 

 that a. proportional amount of time should be given to a 

 study of the organs of flowerless plants, and it is hoped 

 that this will become practicable in an increasing number 

 of schools. Under the present circumstances it has not 

 been thought wise to take the space that would be required 

 for specific laboratory directions, but the following general 

 scheme, with suggestions as to material, may prove service- 

 able to such teachers as are desirous of extending their 

 work in this direction. 



