204 BOTANICAL GAZETTE [ APRIL 
AN UNUSUAL paper has appeared on Drosera rotundifolia. It is a cyto- 
logical and physiological study of this interesting plant by Otto Rosenberg * 
of Stockholm, whose investigations were conducted chiefly at Bonn. The 
examination is suggestive of methods of study in cytology that are soon likely. 
to come to the front, namely, studies upon protoplasm that has been subjected 
to various conditions in the attempt to analyze the factors that influence its 
minute structure. 
The paper is divided into two parts: the first, on forms of nuclear divi- 
sion, and the second, on the physiological behavior of the nucleus. The first 
part considers mitoses in various tissues, reproductive and vegetative. One 
notes that the spindles in vegetative cells are developed from caps of kino- 
plasm, and in the pollen mother cell the presence of a delicate zone of 
granular kinoplasm and fibrillae encircling the nucleus indicates the beginning 
of the achromatic part of the nuclear figure. However, the account of karyo- 
kinesis in the pollen mother cell is not sufficiently detailed to offer evidence 
on disputed points; it appears that the nucleus is small and not altogether 
satisfactory for such a study. 
the physiological studies upon the nucleus the most interesting are 
naturally those on the cells in the tentacles of the leaf. The most fruitful 
studies consisted of an examination and comparison of certain epidermal 
cells before and at successive intervals after the leaves had been fed with 
various substances. These experiments were tried with a variety of foods, 
other organic substances, and with such inorganic salts as borax, calcium 
nitrate, calcium phosphate, and ammonium oxalate. 
eeding the leaves with organic material brings about very shortly 
changes in the cytoplasm and nucleus in the epidermal cells of the tentacles. 
Peculiar granules appear in the cytoplasm near the nucleus, and the tannin 
vacuoles become more prominent. But the most conspicuous effects are 
exhibited in the nucleus. The chromatin increases greatly in quantity along 
the linin network, and finally collects as longer or shorter rods on the mem 
brane. Finally, when the reactions are most energetic, the chromatin takes 
the form of a thick thread and the linin network cannot be followed. The 
nucleolus during this process of feeding usually grows smaller and smaller 
until it is very insignificant. But there is no fixed relation between the 
decrease in the size of the nucleolus and the great increase in the amount of 
chromatin. ; 
These reactions affect other cells in the tentacle, those of the endoderm!s 
and stalk exhibiting similar changes. . 
In general one may say that the feeding of a leaf almost always results In 
ROSENBERG, O.: ase ina -cytologische Untersuchungen iiber ~~ 
mulches L. Upsala 1899 
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