L52 BOTANICAL GAZETTE [AUGUST 
Spraying with Bordeaux mixture is recommended as a preventive measure 
for this disease.— ERNsT A. BESSEY. 
Dr. BRADLEY M. Davis has recently published’ some interesting studies. 
on the nucleus of Pellia. These studies were undertaken with the object of 
extending our knowledge of the cytology of the Hepaticae, and with the hope 
of throwing some light on the relationships of the various morphological 
manifestations of kinoplasm. To accomplish this three phases in the life 
history of the plant were examined, namely ee the germination of 
the spore, and the vegetative activities in the seta. In the spore mother cell 
the spindles are organized in the same manner as that characteristic of the 
asters with centrospheres were found during the prophase. These appear to- 
be transitory structures, however, as they disappear before the daughter 
nuclei are formed. In the vegetative cells the spindles are formed in essen-- 
tially the same fashion as that described by Hof and Nemec for the vegeta- 
tive cells of many spermatophytes. The kinoplasm here forms two caps. 
fitting closely over the ends of the nucleus which has become elongated, and 
these caps are changed into the poles of the spindle. The writer concludes, 
however, that the kinoplasmic fibrillae, the centrospheres, and kinoplasmic 
caps are all secondary developments from the primal granular protoplasm 
which is the only form of kinoplasm in any sense permanent in the cell. 
The paper forms an extremely interesting contribution and contains much 
that is of importance on the cytology of the Hepaticae.—A. A. LAWSON. 
CENTROSOMES in flowering plants are described by Bernard® in a series- 
of short papers. Froma study of Lilium candidum, L. Martagon and Helosis 
Guayanensts the writer convinced himself of the presence of the much dis-- 
cussed structures. Material was fixed in alcohol and in Flemming’s solution 
and was stained in a mixture of fuchsin and iodine green (1 per cent. aqueous- 
solution of fuchsin, 2 parts; 1 per cent. aqueous solution of iodin green, 2 
parts and water 40 parts). The safranin gentian-violet orange combination: 
did not give as good results. 
_ In L. candidum the centrosomes were found quite regularly during vari- 
ous phases in the germination of the megaspore. They resemble the structures- 
described by Guignard, but are not so sharply defined. The centrosome was: 
also identified in the gametophytes of Helosis. In Z. Martagon centrosomes 
were found in the female gametophyte, in the vegetative cells of the ovule,. 
but could not be positively identified in the endosperm. The centrosome | is- 
cytoplasmic in origin. 
7 Nuclear studies on Pellia. Ann. Bot. 15: 147-180. pls. ro-r7. IgOT. 
® BERNARD, C. H.: Recherches sur les sphéres attractives chez Lilium ene: 
Helosis Guayanensis, etc. Jour. de Botanique 14: 118-124, 177-188, 206-212. pis. 
¢-5- 1900 
