8 
Research Bulletin No. p 
it as a new species. He told the writer in 1913 that he felt con- 
vinced that we had described one and the same thing. Comparative 
studies made by the writer during the past year verify this point of 
view, and since the Nebraska publication by Wilcox, Link, and 
Pool (40) did not appear in print until 1913, the name F. trick o- 
thecioides should be adopted. 
WoLLEN WEBER (41, 42) published a further paper in which 
he categorized the Fiisarium spp. very sharply, dividing the genus 
into sections on the basis of physiological (that is, pathogenicity) 
and morphological (that is, conidia and chlamydospores) char- 
acters. F. oxysporum was again established and taken as the 
representative of the section Elegans, which comprises vascular 
parasites; and F. trichotliecioides was put into the section Dis- 
color, which comprises parenchyma destroyers. He distinguished 
sharply between these and also between the vascular ring-discoloring 
Fusarium species of section ElegatsS and the tuber-rotting 
Fiisarium species of sections Discolor. Gibbosum, Martiella, etc. 
Referring to the papers by Smith and Swingle (35), Manns 
(24). and others, particularly to that by Manns, he writes: "They 
do not separate fusarioses causing tuber rot from those causing 
both the wilt diseases of the plant and ring discoloration of the 
tuber, so that the reader might conclude that both wilt disease 
and tuber rot are caused by the same organism." Referring to 
his own experiments, he writes: "It also brings out the striking 
fact that the fungus, a typical xylem inhabitant, does not entirely 
destroy the tuber without the help of tuber rot Fusarium or 
bacteria," and "the fact that F. oxysporum causes the wilt of 
growing potato plants and only uses the xylem of the stem end 
of tubers for over-wintering, without producing a rot of the 
]5arenchyma, leads to interesting comparisons with the following 
4 species which are able to destroy the tuber entirely from arti- 
ficial wounds, namely, F. coeruleum (Lib.), F. trichothecioides 
Wr.r etc., and finally "the fact that the latter (F. ox\sporum) 
cannot produce a tuber rot gives a biological contrast to the 
wound parasites of the tuber, and the fact that they cause the 
wilt disease of the growing plant presents a contrast to the 
saprophytes." 
