1914] MARTIN— LEGUMINOSAE 157 



So far as observed, a longitudinal row of 4 megaspores is always 

 formed and the lower one functions (figs. 7, 8). 



Xo chromosome counts were made, but the number is small and 

 probably the same as in Trifolium repens, where it is about 12. 

 The functioning megaspore rapidly destroys the surrounding tissue. 

 The encroachment is at first most rapid at the chalazal end and 

 results in a tubular sac (figs. 9, 10). As the megaspore enlarges, 

 the tip of the nucellus thickens and with the surrounding portion 

 of the inner integument becomes packed with starch (fig. 10). 

 The megaspore divides in the direction of the long axis of the sac 

 and the daughter nuclei pass to opposite poles (fig. 9). The fol- 

 lowing divisions may be parallel or transverse to the long axis of 

 the sac (figs. 10-12). The longitudinal divisions are no doubt 

 associated with the narrowness of the sac and occur most often in 

 the antipodal end. As the embryo sac matures, it destroys the 

 micropylar end of the nucellus and becomes much larger in this 

 region (fig. n). When the sac is mature, only the basal portion of 

 the nucellus remains and the embryo sac lies against the inner 

 integument (fig. 13). Sometimes the nucellus is more persistent, 

 as shown in fig. 12. 



The polar nuclei usually meet on the median line of the sac 

 close to the egg apparatus (fig. 12), but occasionally they lie against 

 the inner wall of the sac. Fusion awaits fertilization, but was 

 found to occur if fertilization was prevented. Fig. 14 shows the 

 fusion of the two polars before fertilization. In this case pollina- 

 tion was prevented and the ovaries were killed soon after the 

 flowers began wilting. 



The synergids often show a distinct filiform apparatus (fig. 14), 

 which becomes more prominent if fertilization is prevented. The 

 antipodals are ephemeral and no trace of them is left at the time 

 of fertilization. 



Fertilization.— The fusion of the sex nuclei was not seen, 

 although many flowers were pollinated and killed at various periods 

 ifter pollination. The time between pollination and fertilization 

 varies. Flowers pollinated during the high temperature of July 

 and killed 18 hours after pollination showed pollen tubes entering, 

 egg in first division, and 3-celled embryos. In October, when the 



