FORMATION OF THE EMBKYO. 



307 



two embryos in the seed of the Mistletoe ; and there is usually a 

 plurality of embrj'os in Pines and other Gymnospermous plants 



519 



550 



551 



552 



553 



(560), though all but one 

 are more commonly abor- 

 tive or rudimentary. There 

 are other striking peculiar- 

 ities in the fecundation of 

 Pines, &c., which, however, 

 cannot be readily explained without 

 entering into more detail than is 

 here advisable.* In Pines and their 

 allies, moreover, the embryo is not 

 developed until a long time after the 

 application of the pollen, and the 

 filling of the embryo-sac with the 



cellular tissue Avhich forms the basis of the albumen of the seed ; 



the fruit and seed of 

 true Pines, as is well 

 known, not maturing un- 

 til the year after that 

 in which the blossoms 

 appear. 



580'. Tlie further development and the structure of the embryo 

 and tl*e seed must be considered after the Fruit, of which it consti- 

 tutes a part. 



554 



555 



556 



557 



* See Ilofmcister, Untersurhungen, &c. : Rcsearclies into the Fertilization, &c. 

 of the higlier Cryptogamia and tlic ConiferiE (Leipsic, 1851), with seven plates 

 devoted to the embryology of Conifera3. 



FIG. 549. Diagram of the suspensor and forming embryo at its extremity. 550. The same, 

 with the embryo a little more developed. 551. The same, more developed still, the cotyledons 

 faintly indicated at the lower end. 552. Same, with the incipient cotyledons more manifest. 

 553. The embryo nearly completed. 



FIG 554 - 556. Forming embryo from a half-grown seed of Buckwheat, in three stages. 

 557. Same, with the cotyledons fully developed. 



