234 BOTANICAL GAZETTE [octoses 
(C. Amaranti Schw. C. amarantacearum Zal\,). The form described 
by Zalewski (’83) as a different species was not met. Oospores 
are very abundant on both leaves and stems, producing on the 
former characteristic blister-like patches that assume a blackish 
hue if the oospores ripen in sufficient quantity. In the stems 
their presence may be predicted from peculiar swellings, usually 
accompanied by a reddish coloration, the entire plant often 
being thus affected. In partially diseased plants the oospores 
are likely to be found in the inflorescence, which reacts much as 
does the stem, becoming swollen and red. The parts most favor- 
able for study are the stems, but leaves and flowers often set 
tion more easily. In killing the material undesirable parts were 
cut away, and the portions apparently favorable were cut into 
small bits; leaves were scored, and stems and peduncles were 
cut in pieces about 2 to 4°™ long, deep incisions being made 
every 2™™ to give ready access to the killing agent. The killing 
with suitable solutions was apparently perfect, and was as good 4 
midway between incisions as where the solution immediately 
reached the tissue. : 
The killing agent giving the best results was chrom-aceti¢ 
acid of the following formula: chromic acid 0.8 per cent., acell 
acid 0.5 per cent. in water. The material was usually eft in this 
solution from twelve to eighteen hours, then washed in five of . 
six changes of water, allowing about two hours between change 
It was then successively transferred to 12, 25, 5% 
alcohol, remaining about two hours in each grade, ‘ 
in the last grade until it was practicable to imbed in pat . 
variation in the above method, by which the material page 
six days in chrom-acetic acid gave interesting results. 
dered theoil in the protoplasm much less soluble, 
the loss of many of the details of the mitoses. 
Flemming’s chrom-osmic-acetic acid was em 
same manner as the chrom-acetic acid, but was 
since the sections were very much darkened by t 
thus necessitating elaborate methods of bleac 
desirable stain could be obtained. 
ployed i” 
not so ust g 
he osmic a — 
hing before * 
