Apr a8.J9»3 Species of Fusarium Isolated from Potato Tubers 
359 
The conidial measurements of the comma type of spore are as follows: 
o-septate, ii by 4 (6 to 19 by 3.5 to 4.5) microns. 
1- septate, 15 by 4 (12 to 24 by 3.5 to 5) microns. 
9 -septate, 20 by 4.5 (18 to 26 by 4 to 5) microns, 
3- septate, 26 by 5 {ig to 34 by 4.5 to 6) microns. 
4- septate, 32 by 5 microns. . 
ilie percentages of o-, i-, 2-, and 3- septate conidia vary in different cultures. In 
most cases i-septate conidia predominate. 
Fusarium subpalUdum var. roseum Sherb. (Description taken from No. 15, 17,® 22, 
and 40.) 
Macroconidia typically dorsiventral, dorsiventrality distinct, ventrally ciu^ed, 
more or less uniform diameter, apex not long, rounded; base pedicillate. 
Spores in small salmon-colored sporodochia, occasionally merging into psejido- 
pionnotes. Microconidia absent. Chalmydospores sometimes foimd, both conidial 
and mycelial intercalapr. Mycelium somewhat varied in color, white above to 
salmon orange below with some shades of pu^le on potato plug; flesh pink to light 
coral i)ink and rose pink with occasional slight tint of purple or yellow on potato 
agar with 5 per cent glucose. 
Substratum, colorless to rose pink on potato agar with glucose. 
The conidial measurements are as follows: 
x-septate, o to 20 per cent, 18 by 4 microns. 
2- septate, rare (no measurements made). 
3- septate, 50 to 90 per cent, 25 by 4.5 (i6 to 30 by 3.5 to 6) microns. 
4- septate, o to 15 per cent, 34 by 5 microns. 
5- septate, o to 12 per cent, 34 by 5 microns. 
It is doubtful whether there is enough difference between the species 
Fusarium svhpallidum, F. subpallidum var. roseum^ F, clavatum^ and 
F. discolor to warrant more than one species. 
Fusarium clavatum Sherb. (Description taken from No. 23, 4i» 42, and 43.) 
Macroconidia typically dorsiventral, dorsiventrality distinct, ventrally curved, 
slightly broader toward the apex, apex rather abruptly attenuated, base distinctly 
pedicillate. 
Spores in small sporodochia, later merging into pseudopionnotes from pale flesh 
to salmon colored on oat and lima bean; light coral red to coral red on potato agar 
with 5 per cent glucose. 
Microconidia absent. 
Intercalary conidial chlamydospores sometimes present, mycelial intercalary 
chlamydospores occasionally found or scattered. 
These cultures showed unusually close identity culturally and microscopically 
throughout. 
The conidial measurements are as follows: 
1- septate, rare. 
2- septate, 2 to 6 per cent. 
3- septate, 75 to 90 per cent, 27 by 4.5 (16 to 40 by 4 to 6) microns. Average limits 
20 to 30 by 4 to 5 microns. 
4- septate, 15 to 30 per cent, 30 by 5 microns. 
5- septate, 5 to 15 per cent, 30 by 5 microns. 
Practically speaking, the spore measurements and the percentages of 
the variously septated spores varied no more between the different media 
(potato glucose, oat, and lima bean agars) than between different cul¬ 
tures grown on the same medium. 
No. 16 seems to vary between F. clavatum and F. suhpaUidum var. 
roseum and F. discolor in color characters, but the spores agree with 
F. discolor in shape and size, and sometimes in average number septa- 
tions. We, therefore, are identifying it as that species. 
« Practically no normal spores were fotmd in any of the cultures of No. 17 on any of the media used. The 
culture seems attenuated. However, from the few spores and from earlier cultural notes we identified 
it with this q^ecies. 
