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1900] THE CELL PLATE IN HIGHER PLANTS 75 
spore mother cell of Anthoceros and has found that the cell 
plate is formed upon cytoplasmic strands (not spindle fibers) 
uniting the four chromatophores. A portion of this cell plate 
becomes converted into a cell wall. 
In endosperm formation there are a great number of nuclear 
divisions that are not followed directly by divisions of the cell. 
The spindle in each case disappears after each nucleus divides.3 
When the above process has continued until there are a great 
many nuclei lying free in the protoplasm, new fibers are formed 
connecting each nucleus with all of its immediate neighbors. 
In these fibers the cell plates are built in the usual manner. In 
a later work‘ these new fibers were described as growing out 
of a hyaline plasma mass around each nucleus. 
On the nature of the cell plate elements, 7. ¢., the granules 
which form the cell plate, we have an interesting statement. 
The cell plate is formed of small granules whose chemical nature 
is hard to determine. That they may be starch is indicated by 
the fact that they take in some cases a blue stain when treated 
with iodine. In most cases, however, they are not thus stained. 
They may be a substance between starch and cellulose. This 
hypothesis is rendered more probable by the fact that the cell 
plate elements are apparently used directly to form a cellulose 
= instead of being converted into a protoplasmic layer which 
Splits and excretes a cellulose layer between the halves. 
In the pollen mother cells of the Cycadacex, Juranyi® 
described a process of cell wall formation by the conjunction of 
4 cellulose ring, growing in from the mother cell wall and a new 
wall formed in the connecting spindle. 
In 1882 Strasburger modified his previous view as to the 
°rigin and chemical] nature of the cell plate elements.” In this 
Paper he holds that with the aid of suitable stains it can be shown 
*STRASBURGER, Op. cit., p. 345. 
4 
Ueber Kern- und Zelltheilung im Pflanzenreich. Hist. Beitr. 1. 1888. 
‘Zellbildung u 
‘ius nd Zelltheilung, 3. Aufl., 342. 
a thej ve : 
19:31, — tiber Structur u, Bildung des Zellkernes. Ref. in Botan. Centralb. 
7U 
eber den Bau u. d. Wachsthum der Zellhiute 172. Jena, 1882. 
