358 
Journal of Agricultural Research 
Vol. XXlV,JNo. 4 
considerably in size. This variation in size seemed to bear no consistent 
relationship to numbers, age, media, of temperature. We are there¬ 
fore including in the limits given the various sizes of the spores measured 
on the different cultures. 
Fusarium oxysporum Schlect. var. asclerotium Sherb. (Description taken from No 
21, 24, 25, 27, 28, 29, 31, 45, 46, and 58. 
Macroconidia typically dorsiventral, doesiventrality sometimes slight, usually 
distinct, and if so, ventrally curved. More or less uniform in diameter, with more 
or less abruptly attenuated apex; base pedicillate. 
Microconidia very abundant. Oftentimes no macroconidia present, especially 
in cultures that have been kept for some time in stock. Chlamydospores common, 
mycelial intercalary and terminal, conidial intercalary. 
Mycelium abundant, fine and long, from white to slight purple tint to haema- 
toxylin violet to mulberry purple on hard oat agar grown in the dark; white to 
slight development of pinki^ pigment and sometimes purple color on potato plug 
grown in dark; white to slight purple tint on potato-glucose agar grown in darkness 
and white to cameo pink to petunia violet when grown in the light. 
Substratum colorless to purple to dull purpliSi black on potato-glucose agar. 
The conidial measurements are as follows: 
1- septate, few, 22.5 by 4.5 microns. 
2- septate, rare, none measured. 
3- septate, 50 to 100 per centj 34 by 4 (22 to 52 by 3 to 5 microns). 
4- septate, o to 40 per cent, 48 by 4.5 (35 to 60 by 4 to 5 micronsh 
5- septate, o to 20 per cent, 48 by 4.5 (35 to 60 by 4 to 5 microns). 
Fusarium sclerotioides Sherb. var. brevius Sherb. (Description from No. 59.) See 
Plate 2, A. 
Macroconidia typically dorsiventral; dorsiventrality distinct, ventrally curved, 
dorsally elliptic, typically broader toward apex, indistinctly pedicillate; gradually 
attenuated, pointed apex. 
No sclerotia, no plectenchymic sporodochia. 
Microconidia abundant, oval, o-and i-septate. 
Sometimes far in excess of macroconidia. 
Intercalary mycelial chlamydospores common. Mycelium well developed, white 
to mulberry purple on hard oat agar; white to cameo pink and petunia violet when 
grown in the light on potato glucose agar; slight development of pinkish pigment 
on potato ping. Substratum on potato glucose agar livid pink to dark maroon purple. 
'file conidia measurements are as foHows: 
1- septate rare, 22 by 4 microns. 
2- septate rare, no measurements made. 
3- septate 50 to 80 per cent, 36 by 5 (25 to 40 by 4.5 to 5.5) microns. 
SKCTION DISCOI,OR 
Three distinct groups, namely A, B, K, and one group C, which varied 
considerably within itself, contained species included in Wollenweber’s 
section Discolor. The description of these cultures with their identifica¬ 
tion follows. 
Fusarium irichothecioides Wr.; (Description taken from No. i, 3, 5, 6, 7, 8, 9, 10, ii, 
12, 14, 33» 38, 61, 63, 64, 76, 79, 81, 83, 91, and 97.) 
Conidia not differentiated into macroconidia and microconidia, but there are 
two types of spores, the comma and the discolor types. The discolor type, that is 
conidia shaped like those of Fusarium discolor, is very rare. Comma type of spore 
slightly dorsiventral to straight, diameter more or less uniform, apex and base not 
differentiated roimded. (PI. 2, B.) 
Spores in powdery masses, at first on aerial mycelium, which soon covers the surface 
completely. 
Terminal and intercalary chlamydospores occasionally noted. Mycelium abundant 
at first and white, soon becoming covered with powdery spore masses, which vary 
from pale flesh, salmon buff, chamois to buckthorn brown on potato-glucose agar; 
pale flesh to pale pink to pale pinkish buff on potato plug; white to pale flesh to 
safrano pink to light ochre to salmon buff on oat agar. 
Substratum colorless to somewhat darkened on potato-glucose agar. This species 
is easily identified by its very characteristic powdery growth. 
