364 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3 d Ser. 



EXPLANATION OF PLATE LIII. 



(Reduced about one-third). 



Fig. 29. First division of the embryo: X 430. 



Fig. 30a, b. Four-celled embryo; "Type III" of Norner: X 430. 



Fig. 31. Basal cell of embryo has divided to form the suspensor; "Type I " 



of Norner: X 430. 

 Fig. 32. Same stage as fig. 31; "Type II" of Norner: X 430. 

 Fig. 33. Seven-celled embryo; dotted lines indicate the connection of the 



embryo to the micropyle: X 430. 

 Fig. 34. Embryo in which quadrants have formed in the first segment : 



X 43c 

 Fig. 35. Embryo in which octants have formed in the first segment, quad- 

 rants in segment two, while the third segment has divided but 



once: X 430. 

 Fig. 36. Separation of plerome in the second segment: X 430. 

 Fig. 37. Differentiation of the plerome in the first two segments: X 320. 

 Fig. 38. Cutting off of the dermatogen: X 430. 

 Fig. 39. Section nearly median of young embryo, in which the primary 



tissues are cut off: X 400. 

 Fig. 40. Somewhat older embryo than that shown in the preceding figure: 



X 320. 

 Fig. 41. Nearly mature embryo; st, stem; cot, cotyledon; r, root: X 280. 

 Fig. 42. Cross-section of older embryo with the wings of the scutellum, the 



plumule sheath, and young leaves showing: X 140. 



