THE SPRUCE FIR 283 



Angiospcrms, for its function only consists in con- 

 veying the generative cells through the tissues of the 

 nucellus. 



On the side of the female organs, the differences 

 as compared with Angiospcrms decidedly outweigh 

 the resemblances. 



The filling of the embryo-sac with an extensive 

 endosperm or prothallus before fertilisation is exactly 

 what we shall find occurring in the highest Cryptogams, 

 but is quite different from anything in Angiosperms, 

 where only a few cell- divisions intervene between the 

 formation of the embryo-sac and that of the ovum. 



The archegonia, with their multicellular necks, 

 are quite foreign to the typical Phanerogams, while 

 they agree in every detail with the female organs of 

 the higher Cryptogams. In fact, we may say that 

 from the formation of the embryo-sac up to the act 

 of fertilisation the whole development is cryptogamic. 



The embryology, on the other hand, though highly 

 peculiar, is not of such far-reaching significance, for 

 the mode of development varies greatly among the 

 Gymnosperms themselves. 



The seed is still a marked phanerogamic character ; 

 in fact, after fertilisation, the differences from 

 Angiosperms become much less marked. 



The Gymnosperms are known, from geological 

 evidence, to be enormously more ancient than any 

 other Flowering Plants ; they still retain many of the 

 characters of their yet more primitive cryptogamic 

 progenitors. l 



1 See Part II. (Flowerless Plants), p. 31. 



