1912] PACE— PARNASSIA 



3" 



mass 



and so it is not easy to show it correctly. Each of these spindles 

 shows the thickening of the spindle fibers in the center, characteristic 

 of early wall formation, but further development of the walls does 

 not take place, as is shown in fig. 36. The nucellar layer is repre- 

 sented by a more or less distinct line of stuff which can be traced to 

 the perfect cells below the sac. The darker thicker 

 micropyle is probably the remains of the megaspores. 



The eight nuclei arrange themselves in the usual fashion (fig. 

 37)- In this figure the egg lies just back of the synergids and only 

 the lower part of it is shown in the drawing; and the polars are 

 almost in contact. Here the large nucleoli characteristic of these 

 nuclei are well shown, the nuclei having very little other stainable 

 material in them. In this case practically all of this material is 

 shown in the drawing, which was made not with a single focus, but 

 by focusing in all parts of the nuclei. At any given focus one's first 

 impression of the nucleus is an empty circle except for the very large 

 nucleolus. The inner layer of cells of the integument is drawn on 

 only one side of the sac. This layer has the appearance of the 

 so-called tapetum or jacket layer formed in many of the Sympetalae, 

 as well as in other forms, and is quite different in appearance from 

 the adjacent cells. Chamberlain (i) has shown it in Aster novae- 

 angliae. Eichinger (6) says: 



Bei unserer Parnassia kann man fuglich von einem Tapetum nicht 

 sprechen, die innersten Zellen des Integuments unterscheiden sich nicht all- 

 zusehr von den andern. 



But in my material the difference in shape and staining was striking. 

 Small vacuoles are already present in the synergids. One 

 synergid shows the beginning of the indentation, Leiste of 

 Strasburger (21), which in later stages gives a caplike appearance 

 to the upper part of the synergid. It seems to be 



the 



cytoplasm of the sac, that is, it is always just where the cytoplasm 

 of the sac reaches its highest point of contact with the synergid. 

 It seems probable that, as the filiform apparatus develops (being of 

 cellulose, it is somewhat stiff) and the synergids elongate, this upper 

 stiffer part does not change shape so much as the lower part. A 

 filiform apparatus is common in angiosperms, but it is not always so 

 strikingly developed as here. In Die Angiospermen und die Gymno- 



