1900 } fe CELL PLATE IN HIGHER PLANTS 155 
nodules (figs. 4, 27¢). In this case it looks as if the activity of 
a fiber previously described as beginning near either daughter 
nucleus and going toward the equator, has become localized at 
the latter point, producing a swelling on the fiber. The pro- 
duction of such a swelling is accompanied by the further short- 
ening of the fiber (fig. 27c), showing that there has been an 
actual transformation of the substance of the fiber in the for- 
mation of the cell plate element. While the above described 
process seems to agree with the older observations of Stras- 
burger that the substance of the cell plate elements has flowed 
in the fibers to the equator,37 it should be noted that there 
" nothing in the process I have described to indicate a collec- 
tion of smaller granules within the fiber, but that the fiber itself 
has changed... The whole process seems to indicate a somewhat 
plastic character of the fiber. 
The time relative to other phases of mitosis at which the cell 
plate elements occur seems to vary in the onion and the larch. 
In the former their appearance is concurrent with or closely fol- 
lowing that of the carbohydrate material. The chromosomes 
have begun at this time to form slightly denser masses, prepara- 
‘ory to the reconstruction of the daughter nuclei, but separate 
chromosomes may still be distinguished. In the larch, the 
Process of reconstruction goes so far before the cell plate ele- 
rpg appear that the daughter nuclei are often clearly outlined 
a = 4). Whether this difference has any special signifi- 
Sais Si Sealed ries It would be interesting to compare a wider 
lety of forms in this respect. 
: a as the elements can be detected, they seem to form 
cating rie the thickness of the original spindle, indi- 
stages ma i ey are emultancous in their origin. Very early 
ful isch ave escaped observation, however, although Ae 
tise tight i made for them. That such a progressive forma- 
fend & wi the case would be suggested by such cue 
cell plate ele ere there are some peripheral fibers on whicl 
r ments have not yet formed. On the other hand, it 
&. p. 75 of this paper, ‘ 
