43° 



BOTANICAL GAZETTE , [may 



latter finds that it may occur anywhere in the sac of the Scrophu- 

 lariaceae studied by him. In P. secundiflorus polar fusion was 

 found to take place anywhere, seeming to be more a matter of 

 chance than any regulated procedure. Regardless of where 

 polar fusion takes place, the polar fusion nucleus is always found 

 in the bulbous micropylar end of the sac at the time of fertiliza- 

 tion (figs. 6, 7). It is here that the triple fusion is completed. 

 By the time polar fusion is completed the egg apparatus is well 

 formed and the antipodals have begun to disintegrate. In only 

 one case were the antipodals observed to form anything resembling 

 cell walls. The mature embryo sac (fig. 5) is one of the commonest 

 stages of the sac to be found. This is probably due to failure to 

 pollinate at once. A short period of inactivity always seems to 

 occur. 



The mature embryo sac is interesting in that it is always well 

 filled with starch (figs. 6, 7). As soon as the megaspore begins 

 its development into the embryo sac, traces of starch are to be 

 found in it, although it is not until the embryo sac is well matured 

 that large quantities of starch are present. Very often the adjacent 

 tissues contain much starch also. After fertilization, when the 

 endosperm and the embryo begin to develop, the starch in the sac 

 disappears entirely. Many of the grains found in the sac are large, 

 reaching 30 ju or more. Although starch is to be found in either 

 end of the embryo sac it is always much more abundant in the 

 micropylar end. Schmid has found this to be true also. 



False polyembryony 



The fusion of 2 ovules appears to be a much more uncommon 

 occurrence than the formation of 2 or more embryo sacs in a single 

 ovule. Miss Mitchell discusses a single case which she found 

 in Striga lutea. The only other plants in which it has been reported 

 are Pyrus Malus, Loranthus europaeus, and Viscum aibum (4). 

 In the course of this study several cases in which 2 ovules had 

 fused were noted. In some the fusion was quite complete, in 

 others the ovule could be seen to be double. The presence of 2 

 micropyles as well as integumentary tissue between the 2 ^mbryo 

 sacs indicated that 2 ovules had fused. In one instance noted the 



