Apr. 28,1923 Species of Fusariuifi Isolated from Potato Tubers 361 
Martiella, for the blunt spores are very characteristic. The size of the 
spores and number of septations vary considerably, and to identify the 
species and varieties offers many difficulties. 
Sherbakoff (j^), in this group also, has made varieties that could have 
been avoided had he made his species a little more comprehensive, and 
from our experience the characters of some of his species are not suffi¬ 
ciently stable. Such characters are comparative width and length of 
spores, “somewhat narrower macroconidia,” “color of conidia and sub¬ 
stratum usually paler/' “frequent occurrence of bluish plectenchyma/* 
etc* 
After considerable comparative study we have identified No. 30, 35, 36, 
47 > 49> 5i> 53> 74» 80, 89, 90, 94, and 95 as Fusarium solani. Slight 
^fferences occur in these cultures, which, judging from a single photo¬ 
graph or a single set of notes, might suggest a variety of F. solani or of 
F. Martii or even a new species, but study of all of the data shows that 
these cultures do not have sufficiently stable characters to identify them 
as varieties or species. The cultures vary from one another and from 
the descriptions of F. solani only in minor details. Some of these 
variations are shown in the two photographs of F. solanu (PI. 3, A and B.) 
Fusarium solani (Mart. p. par.) Ap. et. Wr. (Description taken from No. 95 as a type.) 
Macroconidia typically somewhat broader in tipper half, rounded to slightly con¬ 
stricted apex, slightly if at all pedicillate. Normally 3-septate 28.75 ^7 4*5 niicrons 
(limits 27 to 38.5 by 4 to 5 microns), sometimes 2- and 4-septate, rarely 5-septate. 
Pseudopionnotes and sporodochia occur commonly on most media. 
Microconidia may or may not be present. When present usually abundant, round 
or oval in shape. Chlamydospores in mycelium terminal and intercalary, common 
in old cultures. 
Aerial mycelium weak to well developed, typically white, neutral gray, sometimes 
with a purple tint. 
Substratum on potato glucose agar usually from deep purplish vinaceous to dull 
violet black. Color on oat agar a mixture of blue, green, and purple. 
Fusarium coeruleum (Dib.) Sacc. (Description taken from No. 55, which was the only 
isolation made of this species.) 
Macroconidia dorsiventral, slightly ventrally curved. Basal end distinctly pedicil¬ 
late. Apex rounded, more or less abruptly attenuated. Uniform diameter throughout. 
Three-septate spores dominant, quite variable, 31 to 42 microns by 5 to 6 microns. 
Aerial mycelium feltlike in age, appressed, white to bluish white and olive buff to 
dusky slate, violet on potato glucose agar. 
Plectenchymatic tissue and substratum on potato glucose agar violet to indigo 
blue and bluish black. 
Chlamydospores very abundant in old cultures, terminal and intercalary and igi 
long chains and masses. 
OTHSR SECTIONS AND UNIDENTIFIED ISOLATIONS 
The few cultures that fell outside of the three sections just discussed 
were identified by means of Sherbakoff's key and descriptions {iS), 
but since we did not have known cultures for comparison, no descriptions 
of them are included here. The identification of each as we determined 
it is as follows: 
Section Gibbosum: No. 20, Fusarium gihhosum. 
Section Roseum: No. 13, F. suhulaium var. hrevius. 
Section Arthrosporiella: No. 69, F. arihrosporioides; No. 72, F. 
anguioidest (Chlamydospores were sometimes found.) 
Section Ferruginosum: No. 75, F. hullatum (may be variety roseum). 
30618—23 - 7 
