Dec. 8, 1933 
Fusarium Stem and Rootrot of Peas 
463 
in mycelium intercalary or terminal, singly or in chains, 8-10 microns in 
diameter. Sclerotia absent or very rare on old rice cultures only. 
Pathogenic in varying degree upon Pisum sativum. 
Differs from F. martii App. and Wr. in having smaller spores, and 
from SherbakofFs variety minus of that species in the smaller diameter 
of its spores, comparative scarcity of sclerotia, and in the predominance 
of green and blue color in conidial masses. 
CULTURAL CHARACTERS 
When the fungus is in a condition of “high culture/' and it is not 
difficult to maintain it in this condition, its appearance upon the various 
ordinary culture media does not differ greatly. The predominant green 
Fig. 1. —Spores of Fusarium martii var. pi si. The last two spores at the right have developed 
chlamydospores. x 1455. 
or blue color of the larger part of the spore mass is a conspicuous char¬ 
acter, at least in older cultures. Production of color varies a little with 
the different strains. The substrate is not greatly discolored, though on 
potato agar rich in dextrose a vinaceous coloration is often produced. 
On rice, it appears that at least two pigments are produced in varying 
proportions. In the earlier development of the fungus a blue color is 
seen at the lower edge of the advancing mycelium,* while a vinaceous 
color is seen predominantly at the surface. These two colors are finally 
mingled through the rice in varying proportions. Sometimes the vina¬ 
ceous color predominates, producing a brownish vinaceous color. If the 
blue predominates, vinaceous drabs are produced. Tendency toward 
the dominance of one or the other of these colors seems inherent in 
strains of the fungus from different sources. 
The morphology of the spores is not much changed upon culture media, 
remaining typical even upon rice (fig. i). Characteristic measurements 
are shown in Table I. 
