1914] M ART I N—LEGUM I XOSAE 161 



(fig. 37) and then move to a position near the egg apparatus (fig, 

 38), where they fuse late, probably not until fertilization. Three 

 antipodals are usually formed (fig. 36), but sometimes only one 

 division occurs in the antipodal end, which results in only one 

 antipodal cell (fig. 37). The antipodals disappear before the 

 embryo sac is mature (fig. 38). 



Embryo. — The egg forms a filament of 5 cells, the terminal 

 one of which produces the embryo, while the other 4 constitute the 

 suspensor (figs. 39. 40). The basal cell of the suspensor is quite 

 long. All the cells have thin, granular cytoplasm and are usually 

 multinucleate. The suspensor is still seen on the advanced 

 embryo (fig. 41). Fig. 40 shows the embryo with derma togen 

 already differentiated. 



Endosperm. — The endosperm takes the parietal arrangement 

 with the earlier development in the micropylar end, but does not 

 mass about the embryo as in the clovers (fig. 40). No sterility 

 was observed in Medicago saliva, but all material used, so far, 

 was collected during rather dry periods, and further investi- 

 gation is necessary to determine the effect of moisture upon its 



fertility. 



Vicia americana 



The number of ovules in Vicia americana has about the same 

 range as in Medicago sativa. The nucellus is smaller, usually hav- 

 ing 3 or 4 subepidermal rows. Periclinal divisions are rapid in the 

 early stage of the nucellus, which give it a slender form. The outer 

 integument, as in Trifolium and Medicago, precedes the inner. 

 Fig. 42 shows 5 archesporial cells, all of which are probably not 

 of hypodermal origin. The development of parietal tissue is vari- 

 able, as shown by figs. 43-45. A row of 4 megaspores is formed 

 (fig. 44) and the lower functions (fig. 45). 



The embryo sac resembles that of Medicago sativa in formation, 

 hape, and in the destruction of nucellar tissue. The antipodal 

 are ephemeral as in the other species (figs. 46, 47), but the posi- 

 tion of the polars is near the inner wall in the middle of the sac 

 ( hg- 47)- It resembles the clover in having much starch in the 

 inner integument and little in the sac. 



