GNETALES 



397 



The embryo cell divides transversely, and this is followed by a 

 succession of divisions in various ]:)lanes until an ovoid mass of cells 



Figs. 448-453. — Ephedra trifurca: development of embryo; fig. 448, one of the 

 proembryos before the formation of the suspensor tube; X500; fig. 449, proembryo 

 with two free nuclei {s, of suspensor; e, of embryo) and a suspensor tube (/); X500; 

 fig. 450, a later stage, showing suspensor (5) and embryo (e); Xsoo; fig. 451, character 

 of the wall, nearly complete, which separates the suspensor and embryo; X 1,900; 

 fig. 452, division of embryo initial cell; s, suspensor; X500; fig. 453, later stage of 

 embryo and secondary suspensor; X250. — After L.and (23). 



is produced (figs. 452, 453). The basal cells of this group elongate 

 successively, forming a multicellular secondary suspensor, which 



