268 
Journal of Agricultural Research 
Vol. II, No. 4 
Fusarium hyperoxysporum has larger but fewer sclerotial bodies on 
potato tuber. Consequently the sporodochia are larger in this species 
than in F. batatatis. A lilac odor is present in cultures on rice, also on 
potato tuber, but weaker, while F. batatatis has a weak alcoholic odor. 
A perfect pionnotes can be easily produced with F. hyperoxysporum on 
potato tuber, but is always accompanied by or embedded in aerial myce¬ 
lium. This fungus resembles more closely F. oxysporum , which, how¬ 
ever, does not produce wilt disease on Ipomoea. While F. batatatis is 
related to F. orthoceras , it differs in characters of the sporodochia, which 
may be compared in the diagnosis. A number of finer details can be 
found. 
8. Fusarium batatatis, n. sp. (Pis. XII and XVI, figs. A-E). 
Diagnosis.—Conidia both scattered and in sporodochia or pionnotes, when scat¬ 
tered mostly unicellular. Conidia mostly 3-septate, rarely 4- and 5-septate, when 
in sporodochia or pionnotes ochreous to salmon colored. Brown chlamydospores and 
blue sclerotial plectenchymata present. Conidia measure as follows: Unicellular 
forms, 5 to 12 by 2 to 3.5/*; 3-septate, 25 to 45 by 2.75 to 47c; 4- to 5-septate, 37 to 50 
by 3 to 4/1. Brown chlamydospores, 7 to iofi thick and similar to those of F. orthoceras . 
The septate conidia are of the same size as corresponding conidia of F. orthoceras and 
differ in shape from F. oxysporum in being a little more slender. The blue sterile 
sclerotial bodies at the base of the sporodochia have a blister-like appearance between 
the felty powdery dry stroma of scattered conidia and push either through the epi¬ 
dermis or stems or the thallus covering the substratum. According to recent investi¬ 
gations of E. E. Harter and Ethel C. Field, this species causes the wilt (stem-rot) of 
Ipomoea batatas by invasion of the fibrovascular bundles of the stems and roots. 
(Collected by Harter and Field.) 
9. Fusarium oxysporum Schlecht. 
Fusartum oxysporum Schlecht., 1824, FI. Berol., pars 2, p. 139. 
Fusarium oxysporum Schlecht., Erw. Sm. and E>. B. Swing., 1904, in U. S. Dept. Agr. Bur. Plant Indus. 
Bui. 55, 64 p., 8 pi. 
Fusartum oxysporum Schlecht., Manns, 1911, in Ohio Agr. Exp. Sta. Bui. 229, p. 299-336, illus. 
Fusarium oxysporum Schlecht., Wollenw., 1913, in Phytopathology, v. 3, no, x, p. 28, 40-45, illus. 
Diagnosis.—Conidia both scattered and in sporodochia or reduced pionnotes, in 
mass ochreous to salmon colored. Unicellular conidia, 5 to 12 by 2 to 3.571; 3-septate, 
rarely 4- and 5-septate, conidia from sporodochia, 25 to 42 by 3.25 to 4.757*. Sclerotial 
plectenchymata blue with rough surface or even sphaerostilbe-like projections. 
Brown chlamydospores, 7 to 1071 in diameter. This species has a slight lilac odor on 
steamed rice and milk. 
Habitat.—A vascular parasite, cause of wilt disease, but not tuber-rot, of Solatium 
tuberosum in the United States of America, districts of South America and Australia. 
Also found on various hosts, such as Eycopersicum, Vigna, Pisum, and Ipomoea. 
10. Fusarium hyperoxysporum, n. sp. (PI. XVI, F). 
Diagnosis.—In morphology of various spore forms and the slight lilac odor, this 
species agrees with F. oxysporum , but differs in having a perfect pionnotes. This 
species, however, differs biologically from F. oxysporum , since it has been proved by 
E. E. Harter and Ethel C. Field to cause a wilt disease (stem-rot) of Ipomoea batatas , 
but not of Solatium tuberosum . On the other hand, F, oxysporum causes the well- 
known wilt disease of Solatium tuberosum , but is not infectious on Ipomoea batatas . 
