14 NORTH AMERICAN SORDARIACEAE 
studied on the substratum on which they grow without being dis- 
turbed. With careful manipulation this can be accomplished in 
an agar-agar culture very conveniently if precautions are taken 
regarding the securing of clean spores. 
The method which has proven most successful with me con- 
sisted in treating a very thin film of the agar with the fungus 
growing upon it in the same way as serial sections are usually 
handled. Cultures were made in nutrient agar-agar in an ordi- 
nary Petri-dish. In the bottom of the dish was placed one or 
more microscopic glass slides and sufficient agar-agar poured in to 
make the thinnest possible film over the slide. Clean spores were 
planted usually near the center of the slide. In about four days 
the cultures were ready for the study of early perithecial develop- 
ment. Much detail can be made out by direct observation of the 
living material, but in order to make permanent mounts consider- 
able patient work is necessary. 
By running a scalpel around the slide, it can be removed from 
the culture together with the film, and placed directly in the 
fixing fluid which one desires to use. A saturated aqueous so- 
lution of corrosive sublimate or Flemming’s weaker solution have 
proven most satisfactory with me. After fixation and washing the 
preparations were stained in either iron haematoxylin or Flem- 
ming’s triple. They were then dehydrated and mounted in 
balsam. 
It is quite a difficult task to carry such a thin film of agar 
through the different solutions, because it is not fastened like the 
ordinary serial sections. It cannot be handled in the staining 
dishes ordinarily used but must be kept in a flat dish which will ad- 
mit the glass slide. The young fungous hyphae retain the stains 
more tenaciously than the agar, consequently a reasonably clear 
background with stained hyphae can be obtained. The retention 
of the gentian in the Flemming method is very difficult on account 
of the slowness with which the film of agar dehydrates. A counter 
stain of orange G is very desirable with iron haematoxylin. 
DEVELOPMENT 
While many of the details of the development of the fruiting 
conditions of these and closely related species have been worked 
