Fig. 82. — Sagiftaria variabilis. Development of embryo. ^4,proembryo of three cells; 

 a, basal cell (in all figures); b, middle cell (dividing); c, terminal cell from which 

 the' cotyledon is derived; sy, synergid; B, same stage, but terminal cell dividing; 

 C, middle cell (6j has divided, .« being the cell from whose derivatives the stem-tip 

 arises, and terminal cell (c) dividing; I), both cells derived from b are dividing; 

 E, terminal cell has given rise to four cells (c), and the region derived from the 

 middle eell , /, , has developed further; F, showing further development of the 

 middle cell region (J), while the terminal cell region has made no further progress; 

 &, dermatogen differentiated in the terminal cell region (c), and the middle region 

 (J further developed ; If. differentiation of dermatogen beyond the terminal region 

 .the middle region (J) showing the differentiation between hypocotyl (h and 

 region producing stem tip; /, more advanced stage, Bhowing satin- regions as in 77, 

 but the dermatogen of the root-tip not yet formed, and the plerome and peri blem 

 undifferentiated. A-F, x 400; G, x 260; II, x 400; I, x 260.— After .S<wiaffner.« 



189 



