3^0 
Journal of Agricultural Research 
Vol. XXIV, Na 4 
Fusarium discolor Ap. and Wr. var. sulphurum (Schlect) Ap. and Wr. (Description 
taken from No. 77 and 85.) 
Macroconidia typically dorsiventral, dorsiventrality distinct, ventrally curved, 
more or less uniform in aiameter. Apex not long, typically slightly broader toward 
the apex, more or less abruptly attenuated, base distinctly pedicillate. 
Spores in pseudopionnotes, nesh ochre to salmon color on all media used. 
Microconidia absent. 
Conidial chlamydospores often found; mycelial chlamydospores never noted, due, 
perhaps, to scarcity of mycelium. 
Mycelium white at first, but soon becoming entirely covered by pseudopionnotes. 
Substratum colorless to slight salmon coloring.^ 
^or photograph of No. 77, see PI. i, C and D.) 
The conidial measurements are as follows: 
2~septate, rare. 
3- Septate, 15 per cent, 24 by 4 (22 to 32 by 4 to 4.5) microns. 
4- 9eptate, 15 per cent, 35 by 5 microns. 
5- septate, 70 per cent, 40 by 5 (35 to 45 by 4 to 5) microns. 
6- septate, rare, 42 by 6 microns. 
The percentages of the different septate spores vary in different cultures. For 
instance, 5-septate spores were 97 per cent on 7-day culture on lima bean and only 
40 per cent on oat about 15 weeks old. The size also varies. The cause of difference 
in size would seem to depend on temperature and moisture conditions quite as much 
as on the medium used. 
No. 84 was much the same as No. 77 and 85 but showed the following variations in 
spore measurements: 
1- septate, rare. 
2- septate, 4 per cent. 
3- 9eptate, 40 per cent, 26 by 4.5 microns. 
4- septate, 30 per cent, 32 by 4.5 microns. 
5- septate, 25 per cent, 36 by 5 microns. 
6- septate, rare, 38 by 5 microns. 
Color of growth lighter on potato glucose, orange tinge with bacterial-like growth 
below. 
No. 52 was much the same as No. 77 and 85 but showed the following variations in 
spor^ measmements: 
3- septate, 12 per cent, 25 to 40 by 4.5 microns. 
4- septate, 8 per cent, 38 by 4.6 microns. 
5- septate, 80 per cent, 42 by 5 (35 to 52 by 5) microns. 
6- septate, rare. 
Spores seem to be slightly less curved than in No. 77, though they grade into each 
other. 
Color of growth slightly different, apricot orange rather than flesh ocre on all media 
used. On lima bean mycelium was medium in growth, contrasted with its scarcity 
in No. 77. 
The darkening of the medium mentioned in note on Fusarium discolor var. sul- 
phureum was never noticed in cultures of this number. 
F. culmorum (W. Smith) Sacc. (Description taken from No. 84, which was the only 
isolation made of this species.) See Plate 2, D. 
Macroconidia dorsiventral, ventrally straight or very slightly curved, slight con¬ 
striction at the apical end and the pedicillate base, quite uniform diameter through¬ 
out, typically 5-septate 36 by 6 microns. 3- and 4-septate conidia are not uncommon. 
Conidia have thick membranes and very pronounced septa. Orange-colored spor- 
odochia found. 
Conidial chlamy dospores abtmdant on lima bean agar, age 175 days. 
On potato glucose agar mycelium abundant, bright pink above, carmine to ox-blood 
red below. 
Substratum ox-blood red. 
SECTION MARTIEI<LA 
The members of the one group (F) that fell within this section were not 
identical in their cultural characters but were sufficiently similar to 
suggest a group. Microscopically it is quite easy to recognize the group 
^ On potato glucose agar, both in the light and in the dark, the medium sometimes darkened to a brown 
black and the growth became more or less powdery, from Sanford’s brown to a nigger brown in color, 
the pseudopionnotes disappearing. Spores mounted from such cultures appeared more or less disin¬ 
tegrated. 
