S Research Bulletin Xo. 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. tricho- 

 thecioides should be adopted. 



WoLLENWEBER (41, 42) published a further paper in which 

 he categorized the Fusarmm spp. very sharply, dividing the genus 

 into sections on the basis of physiological (that is, pathogenicity i 

 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. trichothecioides 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 Elegans and the tuber-rotting 

 Fusarium species of sections Discolor, Gibbosum, Martiella, etc. 



Referring to the papers by Smith and Swingle (35), Manns 

 (24). and others, particularly to that by M \\.\s, 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 will of 

 growing potato plants and only uses the xylem of the stem end 

 of tubers for over-wintering, without producing a rot of the 

 parenchyma, leads to interesting comparisons with the following 

 4 species which are able to destroy tile tuber entirely from arti- 

 ficial wounds, namely, F. coeruleum (Lib.), F. trichothecioides 

 Wr.," etc., and finally "the fact that the latter ( F. oxysporum i 

 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." 



