314 



MORPHOLOGY OF THE ANGIOSPERMS 



proembryo) development in taxa throughout angiosperms, there is a 

 surprising lack of information concerning the stages intermediate be- 

 tween the proembryo and the mature embryo, especially the histology 

 of the origin of cotyledons and stem and root apices, and the time and 

 rate of development of these structures. Apparently, this stage has been 

 considered unimportant, but some aspects of it are of much importance 







.-■■••.-•;«fil^4..^:-!;>:i. 

 - '•■3S7«V;.*-.>..v... 









Fig. 117. Early stages in ontogeny of the embryo of Beta vulgaris. Filament of cells 

 formed by transverse divisions; in E, and F, distal part enlarged by divisions in 

 many planes. (A, B, after Artschwager; C to F, after Artschwager and Starrett.) 



