64 BOTANICAL GAZETTE [JANUARY 
a ae 
of the egg when it contains two astrospheres with the gamete nuclei is of — 
great interest, and this phase of the subject is worthy of extended study. 
I have seen and figured eggs in Saprolegnia with two coenocentra, each 
accompanied by a nucleus, when it was evident that the two were sister 
structures included within the same egg origin. 
It is evident that very much more work must be done both in the Sap- 
rolegniales and Peronosporales before some of the points suggested by 
Trow’s paper will be established. An ovicentrum arising from an aster 
associated with a reduction mitosis is a very different sort of conception 
from our present idea of the coenocentrum in the Peronosporales. The 
same sort of structure is also reported to appear suddenly beside the sperm 
nucleus after its entrance into the oogonium. It seems hardly conceivable 
that similar structures could behave in such different ways or could hold 
relationships to the coenocentra of the Peronosporales. Of course my 
own view of the essential agreement of the Saprolegniales and Perono- 
sporales in processes of oogenesis around coenocentra must await the 
results of future investigations.—B. M. Davis, The University of Chicago. 
THE SEXUAL ORGANS AND SPOROPHYTE GENERATION OF 
THE RHODOPHYCEAE. 
OLTMANNS’s theory that the structure developed from the fertilized 
carpogonium in the Rhodophyceae represents a sporophyte generation has 
received substantial confirmation in recent cell studies of WOLFE? on © 
Nemalion. This investigation also makes an important contribution to 
our knowledge of the sexual organs of the red algae, establishing some * 
complications of structure that are likely to prove very general in the 7 
group, and quite changes our conception of their morphology. Their © 
possible relations to the sexual organs of the lichens, Laboulbeniaceae, and — 
even to the Uredineae is full of interest. 
carpogonium during the early development of the tiehonyee, panes 
to the bottom of the carpogonium. Although no mitotic figure was obser 
it seems clear that the nuclei of the trichogyne and egg are sisters, follow: 
ing a division in the terminal cell of the procarp. 
These observations on Nemalion confirm my account of the trichog} 
* WoLrE, J. J., Cytological studies on Nemalion. Ann. Botany 18:607- 
_ pls. 40-41. 1904. ; 
