328 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



EXPLANATION OF PLATE XLVIIL 



All figures except 69, refer to .S". simplex. 



Two sections of a nearly mature embryo. Oc. i, obj. 3. 

 Root-end of a somewhat younger embryo. The position of the 

 original transverse, or basal wall [x) is still evident, P, the second 

 leaf; st. the stem-apex. Oc. i, obj. 7. 

 Three cross-sections of a mature embryo. Oc. 3, obj. 3. 

 Sections of the young seed before the endosperm has filled the 



embryo-sac; e, embryo; z«', iti^, integuments. 

 Section through the layer of developing endosperm lining the embryo- 

 sac; many of the nuclei are dividing. Oc. i, obj. 7. 

 Larger endosperm-nuclei from the base of the sac at the time the 

 walls are first beginning to form; some of the nuclei have more 

 than one nucleolus; the fine fibres connecting them are plainly 

 visible. Oc. i, im. jV- 



Fig. 58. Trans\erse section of recently formed endosperm-cells showing 

 the nucleolus fragmenting. Oc. i, im. y'^. 



Fig- 59- Upper part of the young seed showing the enlargement of the 

 micropylar portion of the integuments. Oc. 3, obj. 3. 



Fig. 60. Young sclerenchyma-cells from the pericarp. Oc. i, obj. 7. 



Fig. 61. Fully developed sclerenchyma-cell showing the deeply pitted walls. 

 Oc. I, obj. 7. 



Fig. 62. Surface view of the pits more highly magnified. 



Fig. 63. Endosperm-cells from nearly ripe seed, showing large crystalloids. 

 Oc. I, obj. 7. 



Fig. 64. Separate crystalloids more highly magnified. 



Fig. 65. Abnormal embryo-sac of S. simplex; the sac divided longtudinally 

 with the endosperm-nucleus on one side. Three antipodals 

 could be distinguished. Oc. i, obj. 7. 



Fig. 66. Micropylar end of the same sac. 



Fig. 67. One of the antipodal cells of the same. 



Fig. 68. Abnomal embryo-sac (perhaps unfertilized ?) ; there has been little 

 increase in size of the sac, but numerous endosperm-nuclei are 

 present, and the antipodals have enlarged and divided. Oc. i, 

 obj. 7. 



Fig. 69. Two sections of an abnormal embryo-sac of 6". Greenii ; three 

 antipodals could be seen, and the polar-nuclei {p.n.), in close 

 contact, were separated from the body of the sac. The upper 

 part was also shut off by a membrane, and no definite egg- 

 apparatus could be distinguished. Oc. i, im. j'^. 



