408 BOTANICAL GAZETTE [JUNE 
ture on that subject, and has expressed some opinions of his own 
derived partly from the facts as they have been presented by 
various observers and partly as a result of his work on nuclear 
division in the root tip of Phaseolus. He arrives at the conclusion 
that the nucleolus is not an independent organ of the cell, but only 
a part of the nuclear thread in which a considerable portion of 
the chromatin may be stored, and from which it may be withdrawn 
again at the time of chromosome formation. He agrees with 
Drxon (10), therefore, that if the chromatin is the bearer of the 
hereditary qualities, not only the chromatin granules but also the 
nucleolus must be taken into account in any theories on the subject. 
In a number of other plants outside of the Conjugatae the 
nucleolus has been reported as containing the larger part or all of 
the stainable material in the nucleus. GOLENKIN (19) finds in 
Sphaeroplea the nucleolus breaking up directly into chromosomes. 
Wo tre (47) describes all the chromatin in the Nemalion nucleus as 
being stored in the nucleolus. BEER (1) says that the nucleolus 
of the cells of the Riccia thallus contain practically all the chromatin. 
He was able also at times to distinguish in it a composite structure, 
as though it were composed of granules. He believes that the 
spireme thread becomes thickened by the material from these 
granules. He also believes that similar conditions are found in 
one of the mosses (Funaria). 
Escoyez (12) states that the nucleolus in Stypocaulon appears 
to contain the larger part of the chromatin, as the reticulum around 
it stains very lightly in the iron-alum-hematoxylin. The chromo- 
somes are formed from the reticulum, however, and in the telo- 
phase the chromosomes form again a typical reticulum, the 
nucleolus not being formed by their fusion. 
STRASBURGER (40), as a result of the fact that he finds in Mar- 
silia practically all the stainable material collected in the nucleolus, 
draws the conclusion that the linin and not the chromatin may be 
the bearer of the hereditary qualities, while the division of the 
chromatin is only a device to equalize the food supply of the cells. 
The very discrepant accounts of Spirogyra given by different 
investigators, and the very close relationship of Closterium to it, 
make a study of the latter very desirable, especially in view of the 
