78 
OHIO BIOLOGICAL SURVEY 
the microscopic study. Since no method has been developed to preserve 
the gelatinous appendages of the spores, and since the paraphyses and asci 
of many species are so evanescent, the mounts were made as follows: the 
material was mounted in water, which was gradually removed with blot¬ 
ting paper and was replaced by 100% alcohol. This was followed in the 
same way with xylol. After most of the xylol had been removed, balsam 
was added and the cover-glass applied. By this method, the perithecia 
and hairs as well as the spores and their arrangement in the asci could 
usually be preserved for some time. 
The following two methods given by Griffiths could not be tried for 
lack of time and materials: by the one method the object is mounted in a 
drop of two per cent, aqueous solution of chrome alum on the flat slide, 
sufficient pressure being placed on the cover to rupture the perithecia, the 
superfluous liquid being wiped off; the cover is then sealed immediately with 
marine glue: by the other method the objects are mounted in water and 
arranged as desired; then a drop of dilute glycerine is placed at the edge 
of the cover and allowed to stand for two' or three days before sealing. 
Griffiths says that the glycerine mounts are less liable to loss owing to 
imperfect sealing than the others; but they have the disadvantage of show¬ 
ing less detail, which is highly objectionable with such delicate structures. 
The author did not attempt to obtain pure cultures until the year was 
half gone; but in the remaining time he was able to grow several different 
species on ordinary potato hard agar, in pure culture, either by transfer¬ 
ring the spores ejected upon the sterile lid of the Petri dish, or by making 
two or three succeeding cultures each one from the preceding. Usually 
by the last method a pure culture could be obtained in the second transfer. 
Since this paper deals largely with a survey of the species found in 
Ohio, little time could be given to the development of the different species, 
however interesting this may be. So far as noted, the observations agreed 
with those found by Griffiths, and therefore need not be repeated. At the 
end of each description, however, the date of collecting the material and 
the time when growth was obtained are given. It was thought that this 
might be of interest in telling how old were the spores that still retained 
the power to germinate after withstanding the desiccating influence of the 
laboratory. Griffiths has shown that spores of Fimetaria fimicola will 
remain in a normal condition over three and one-half years under the 
desiccating influence of laboratory temperatures and germinate. He also 
produced eight crops of the same species in seventy-five days, each succeed¬ 
ing crop being produced from spores of the preceding one. 
The structure of these plants and the part this plays in spore dissemi¬ 
nation is another phase that time will not permit to be developed in 
this paper. 
