i9 1 2] PACE—PARNASSIA 



315 



ifraga 



Chodat (3, p. 552) says: 



Lorsque le noyau fecondant est entre dans le sac on remarque qu'au moins 

 1'une des synergids perd sa turgescence et se desorganise. 



In his fig. 677 he shows a pollen tube which from the drawing 

 might be either inside or outside of the synergid. In this mass are 

 three nuclei, one evidently the synergid nucleus. Fig. 63 shows a 

 sperm cell in each synergid. There seems to be a distinct layer of 

 fine-grained cytoplasm about each of these nuclei. One synergid 

 also has another somewhat irregular mass of nuclear stuff which is 

 probably the tube nucleus. This sac was cut slantingly, so that the 

 micropyle and filiform apparatus were in another section, but no 

 trace of the pollen tube was found in this region. Another ovule in 

 the same section had an embryo of five cells. But only a very few 

 embryos were present in this ovary, and the other ovules did not 

 show evidence of fertilization; so that probably only a few pollen 

 grains had reached the stigma. These two dark synergids, each 

 containing a sperm cell, might be interpreted as evidence of two 

 pollen tubes in the same sac. But as there is no other trace of 

 pollen tubes or other nuclei, and the egg and primary endosperm 

 nucleus do not have the appearance of having been fertilized, it 

 seems best to suppose that only one pollen tube has entered and 

 that it burst just where the two synergids are in contact. In this 

 way it would be possible for part of the contents to pass into one 

 synergid and part into the other. .Both synergids are quite dark 

 and show little trace of vacuoles, which are quite conspicuous in 

 mature sacs. 



Nawaschin (16) says that after the pollen tube passes the ' 

 micropylar canal and the nucellus of the ovule, and its tip is in 

 contact with the embryo sac, one of the synergids bursts and pours 

 part of its contents into the micropyle. This forms a half-empty 

 tube of this synergid, and the sudden diminution of pressure causes 

 the pollen tube to burst and its contents are poured out next to this 

 synergid into the sac. Then the sperm nuclei begin active move- 

 ment toward the depression in the "Endospermanlage," and move 

 from there to the female cells. In Parnassia it is very evident that 

 the pollen tube passes around the tip of the synergid without either 



