80 BOTANICAL GAZETTE [AUGUST 
fiber substance into a lamella from which is derived the plasma 
membrane of the daughter cells, Strasburger was not then certain 
whether the cell plate forms simply the plasma membranes, or 
whether a part of it may be changed into a division wall (9. aif, 
38). In a subsequent contribution, however, he made the 
statement that the cell plate forms a plasma membrane (Hawt 
schicht), that it splits to form a plasma membrane for each 
daughter cell, and that the substance of the cellulose wall 
excreted by these daughter plasma membranes and laid dowi 
as a wall between them. 
Hof* has recently described in the division of vegetative 
cells what I take to be the same appearance as that described by 
Went and Strasburger, viz., the deeply stained portions of the 
spindle moving toward the equator and there taking part in the 
formation of the cell plate. He, however, describes the sub- 
stance of these zones as granular rather than as material i 
solution in the nuclear sap. After the cell plate is complet? 
the connecting fibers are entirely drawn in (eingezogen) and theif 
place taken by alveolar cytoplasm. Just what Hof means by 
the drawing in of the connecting fibers is a question left unsettled 
in his description. They may be drawn into the nucleus of into 
the cell plate. His figures do not help at all in understanding 
his meaning in this instance. is 
Nemec? has recently described the same phenomena 4 ee 
the formation of the cell plate in the growing root tips of Allin 
Cepa. He adds further that new connecting fibers make thet 
appearance after these zones have reached the equator. The 
fact that these new fibers often seem to end free betwee? the 
original fibers, Nemec considers as evidence for their origin ff™ 
the stained substance now at the equator. : 
The observations of Strasburger as to the method of cell 
plate formation in the oogonium of Fucus were not whol 
88 
z Ueber die karyokinetische Kerntheilung in der Wurzelspitze von A/iu™ aie 
Jahrb. f. wiss. Bot. 32 : 313. 1899. ae 
*3Zellhaute. Jahrb. f. wiss. Bot, 31: 514. 1898. 
*4 Histologische Studien am Vegetationspunkten. Bot. Centralb. 76: 221-3 
