320 BOTANICAL GAZETTE - [ocroBER 
Biology of diatoms.—Cell division is described by BERGON?? for Biddulphia, 
but the nuclear details are not shown. No centrosomes are - ae 
principal point of interest in the formation of auxospores is that not one, but 
two are formed in each cell. Spores (the so-called microspores) have been 
described and the observations have been disputed. Although the existence of 
such spores might safely be conceded, this paper describes the development of 
sporangia and spores so clearly that there can be no doubt either as to their 
existence or the mode of their formation. —CHARLES J. CHAMBERLAIN. 
Sterile anthers of Ribes.—JaNczewsk1°° has discovered an interesting situa- 
tion in the pollen of Ribes. In the genus there is every stage between entirely 
fertile and absolutely sterile anthers. Certain subgenera and a few hybrids 
habitually develop perfect pollen. Most common among the hybrids, however, 
is a mixture of sterile and fertile pollen grains, in varying proportion. r 
tain hybrids and in the subgenus Parilla the pollen is persistently inert. Degener™ 
tion generally occurs after tetrad formation, but sometimes in the mother cell 
stage—J. M. C. 
Protoplasmic rotation.—BrERBERG3" concludes that rotation and streamms 
is neither a widespread nor usually a normal phenomenon, but he does not accept 
ss KELLER’s view that it is a symptom of dying. On the contrary, he fine 
that it accelerates the transfer of materials more than threefold over per : 
move- 
or are or are not permeable in all parts, are less valuable than his experimental ” 
work.—C. R. B. 
Rusts.—O IvE3? has published a popular account of cereal rusts and their 
life-histories. He confesses that “the problem of the prevention of rusts 1S pe 
* difficult one that many points still remain to be solved;” and states that 
main thing which can be done at present is simply to record the present al 
our knowledge as to the nature of these complicated organisms, and to awit" 
interest in a knowledge of their habits.” —F. L. STEVENS. 
29 BERGON, P., Biologie des Diatomées.—Les processus de division, Rev. G 
ment de la cellule et de sporulation chez le Biddulphia mobilensts Bailey : 
Botanique IV. 7: 327-358. pls. 5-8. 1907. : acai Sci. 
3° JANczEwsxt, Ep., Sur les anthéres stériles des groseilliers. Bull. “@~ ~ 
Cracovie 1908: 587-596. pl. 24. " Hofftranspott 
3t BIERBERG, W., Die Bedeutung der Protoplasmarotation fiir den Hi 
in den Pflanzen. Flora 99:52-80. 1908. “Stes 
3? Oxtvg, E. W., Rusts of cereals and other plants. S. Dak. — eo é 
Bull. 109. June 1908. 
