88 BULLETIN 380, U. S. DEPARTMENT OF AGRICULTURE. 
Endothia parasitica gave a scanty white growth of surface mycelium, with 
several prominent pycnidial pustules clustered near the center and of a slightly 
darker shade than the “raw sienna” of Ridgway." 
CULTURES ON POTATO AGAR (SLANTED TUBES). 
Potato agar was used by the Andersons (3) to distinguish Zndo- 
thia parasitica from E’. fluens. The writers have used it extensively 
and found it a very useful medium for distinguishing the species. 
As stated in the previous paper (77, p. 11), however, unless this 
medium was very carefully prepared it varied greatly in acidity 
and probably in other respects, with resultant variations in the 
behavior of the organisms. Spore production was not so abundant 
on this medium as on many others. The preparation of this and 
other media is described in the paper cited. 
Endothia gyrosa.—This species developed rather slowly, producing a fairly 
abundant aerial growth, which was felty rather than fluffy. The color was 
white, flecked with capucine buff, and no spore masses were produced. 
Endothia singularis—This species grew even more slowly than #H. gyrosa. 
On cultures made from conidia, growth was hardly perceptible at the end 
of three days. Mycelial cultures at the end of one week showed less growth 
than H. gyrosa, but did not differ greatly from it in either color or texture. 
At the end of one month the mycelium was slightly more fluffy and decidedly 
less in amount than that of #. gyrosa. Most of the surface was a very light 
buff color, with sometimes a few spots of capucine orange to English red. 
Endothia flwens—Pycnospore streak cultures of this species varied some- 
what as to the amount and time of appearance of color, probably due to the 
variations in the acidity of the medium referred to above. Many tubes 
showed an orange color in one week, while others produced no orange what- 
ever. In no case did cultures of H. fluens produce the “ brassy ” metallic sur- 
face appearance so characteristic of H. parasitica. Pycnidia were few and more 
seattered than in HZ. parasitica and did not begin to appear until the third or 
fourth week. A slight amount of warbler-green color sometimes appeared in the 
medium at this age, but never so conspicuously as in lv. parasitica. 
Endothia fluens mississippiensis—This produced a less fluffy aerial mycelium 
along the spore streak than FE. parasitica. After five or six days the fungus 
showed an orange color by transmitted light, and was indistinguishable in 
this respect from FH. parasitica. The character of the surface was somewhat 
different, however, and by reflected light appeared xanthine orange. When 
two weeks old this form differed still more markedly from 2. parasitica in 
color, being grenadine red by transmitted light and showing no spore masses. 
E. longirostris—At the end of one week this produced a white, fluffy growth 
seattered in small patches over the surface of the medium. This later became 
rather close in texture, especially near the base of the agar slant. No spores 
were produced on this medium. 
Endothia tropicalis—At the end of one week this showed less growth than 
#. fluens, covering about a third of the surface of the medium, while the 
other covered nearly the entire surface. The mycelium was closely matted 
and a very pale buff (paler than any in Ridgway). At the end of one, month 
1In the descriptions of cultures comparisons were necessarily made with cultures in 
flasks or tubes. This of course made comparison more difficult and somewhat less accurate 
than if the material had been removed from the container. 
