276 BOTANICAL GAZETTE [OCTOBER 
lately; end branches 15-30 yw long, in whorls of 3 or 4, tapering to 
a knobbed end which bears a single spore. Conidia oval, hyaline, 
2.2-3.5 win diameter, easily falling away. Chlamydospore forma- 
tion especially common; chlamydospores multicellular, 4-9-celled, 
with granular contents, thick-walled, globular, 10-25 w in diameter 
when mature, slightly lobed, borne on short side branches which 
are 15-30 p long, very persistent.—Fig. 16. 
This chlamydospore-formation is the most characteristic feature of this 
fungus. The older mycelium becomes a complete mass of these, matted in 
with hyphae, which at last disappear, leaving the chlamydospores as a creamy 
or ochraceous powder. The verticillate, conidial fructification forms more 
abundantly in the young mycelium at the edges of the culture, while later 
only chlamydospores are formed. 
III. Assimilation of free nitrogen 
GENERAL PLAN AND METHOD 
In this part of the investigation an effort was first made to 
get some qualitative indication of nitrogen-fixation in a trial with 
all the fungi which had been isolated from the experimental plat. 
After this, it was planned to carry on further investigation with 
exact analytical methods, using any forms which gave any signs 
of such power. In carrying out this plan five separate investiga- 
tions were made. 
tr. Culture solutions of 25 cc. each were prepared in large test 
tubes, which, after sterilization and inoculation by means of spores, 
were allowed to stand in the air protected only by germ-proof 
cotton stoppers. 
2. A similar investigation was carried out, using 150 cc. Erlen- 
meyer flasks instead of test tubes, and using 50 cc. of the nutrient 
solution for each culture. 
Ss Cultures of four fungi, which gave the most hopeful indica- 
tion of nitrogen, were prepared in an apparatus for aerating by 
means of air drawn through sodium hydroxide and concentrated 
sulphuric acid. Each culture contained roo cc. of the culture 
solution. 
4. Cultures similar to those in “3” were put under bell jars 
