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



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 55- 



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EXPLANATION OF PLATE XLVIII. 



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



Two sections of a nearly mature embryo. Oc. 1, obj. 3. 



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

 original transverse, or basal wall {x) is still evident, I 2 , the second 

 leaf; si. the stem-apex. Oc. 1, 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; in 1 , in 2 , integuments. 



Section through the layer of developing endosperm lining the embryo- 

 sac; many of the nuclei are dividing. Oc. 1, 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. 1, im. y 1 ^. 



Transverse section of recently formed endosperm-cells showing 

 the nucleolus fragmenting. Oc. 1, im. T \. 



Upper part of the young seed showing the enlargement of the 

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



Young sclerenchyma-cells from the pericarp. Oc. 1, obj. 7. 



Fully developed sclerenchyma-cell showing the deeply pitted walls. 

 Oc. 1, obj. 7. 



Surface view of the pits more highly magnified. 



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

 Oc. 1, obj. 7. 



Separate crystalloids more highly magnified. 



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

 with the endosperm-nucleus on one side. Three antipodal s 

 could be distinguished. Oc. 1, obj. 7. 



Micropylar end of the same sac. 



One of the antipodal cells of the same. 



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. 1, 

 obj. 7. 

 Fig. 69. Two sections of an abnormal embryo-sac of .S". 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. 1, im. T V- 



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58. 



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60. 

 61. 



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62. 

 63. 



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64. 

 65. 



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66. 



67. 

 68. 



