+o 



CORMOPHYTA 



The fundamental differences between the four main 

 groups are briefly represented in the following table : 



Division 



I. Bryophyta 



Sexual Generation 

 (The Gametophyte) 



9 Sexual Organ 



," Sexual Organ 



Liverwort and Archegonia; in Antheridia, produc- 



Moss-plant. the mosses at ing motile sperma- 



the apex of tozoids. 

 the branches. 



II. Pteridophyta Prothallium <$ 

 i. Isosporous 

 (Fern) 



2. Heterosporous 

 Ex. Selaginella 



III. Gymnosper- 

 mae 



IV. Angiosper- 

 mae 



o # 



Rudimentary 

 prothallium, 

 partly within 

 the macro- 



spore. 



O =K- 



Prothallial tissue 

 (colourless), 

 developed 

 within the 



ovule and 



subsequently 

 transformed 

 into 

 endosperm. 



Rudimentarytis- 

 sne in the nu- 

 cellus, mostly 

 disappearing 

 completely. 



Archegonia, 

 borne on 



under side of 

 prothallium. 



Archegonia, 

 embedded in 

 the rudimen- 

 tary prothal- 

 lium. 



Archegonia, 

 (2 or more), 

 embedded in 

 the prothallial 

 (nucellar) tis- 

 sue of an 

 ovule. 

 Ovules 

 exposed. 



Embryo-sac, 

 enclosed in 

 the nucellus, 

 finally often 

 it. 

 (1 or 

 00 ) enclosed 

 in a carpel. 



filling 

 Ovule 



Antheridia, borne 

 on under side of 

 prothallium, pro- 

 ducing motile 

 spermatozoids. 



Antheridium, formed 

 within germinating 

 microspore and 

 producing motile 

 spermatozoids. 



Microspore (pollen 

 grain), carried by 

 outside agency to 

 the ovule, entering 

 it as a whole. 



1 . Cycadaeeae and 

 Ginghti/c'S. Pollen 

 grain producing 

 motile spermato- 

 zoids. 



2. Coniferae, 

 Gnetrtceac. Pollen 

 grain developing 

 a pollen tube. 



Pollen grain, ger- 

 minating on the 

 stigma; pollen 



tube carrying the 

 generative nucleus 

 passively to the 

 embryo-sac. 



For £ organ see column 4. 



