8 BULLETIN 1284, U. S. DEPARTMENT OF AGRICULTURE 
(71) found it in a volunteer crop of Orange sorgo at Davis, Calif., 15 
per cent of the plants being infected. During the last few years head 
smut has become somewhat prevalent in Red Amber sorgo at the 
Hays (Kans.) Branch Experiment Station, and this has reduced the 
value and popularity of this variety. Freed sorghum also has been 
infected with head smut to a considerable extent. 
The first report of the occurrence of head smut on maize was made 
in 1876 by Cooke (27) , who collected it in India and listed it under 
the name of Ustilago pulveracea Cooke. Passerini 6 in the same year 
described the form on maize in Italy as Ustilago reiliana f. zeae. 
Cugini (28) and Mottareale (75) also have described its occurrence 
in Italy, Bubak (18) records it in Bohemia, Garbowski (42) in Russia, 
and Butler (21) in India, where it occurs chiefly in Kashmir, being 
probably more destructive than Ustilago zeae. It also occurs sporad- 
ically in the Punjab and northern Bombay. Both Mundy (76, 77) 
and Evans (35) report this smut as common in South Africa, and 
McAlpine (69, 70) and Johnston (50, 51) record it as common and 
destructive in Australia. 
The first record of its occurrence on maize in the United States was 
made by Norton (79) in 1895. 7 Norton, and later Hitchcock and 
Norton (48) , described the head smut on maize as not uncommon in 
certain fields in Kansas during the season of 1895. Clinton (26) in 
1906 reported it only from Kansas and Ohio. Mackie (71) in 1919 
found this smut in a field of King Philip hybrid maize near Stockton, 
Calif. Practically all the plants in a restricted area of the field were 
smutted. Dana and Zundel (30, 31) in 1919 found this smut on 
maize in two fields in the vicinity of Pullman, Wash. In one field 
they found 40 per cent of the plants smutted. Parker (81) has noted 
its wide distribution in that State. 
The head smut on sorghum produces a very characteristic appear- 
ance. The entire inflorescence usually is involved and is converted 
into a spore mass protected by a transient whitish membrane. No 
outstanding difference between smutted and normal plants can be 
noted until the heads begin to form. Then a difference in the size 
of the heads is observed, the infected panicles remaining much smaller 
than the normal. As the panicles emerge from the boot the difference 
is very striking. The spores are interspersed with the stringlike 
remnants of the fibrovascular bundles of the host tissue. When the 
membrane breaks, the spores are rapidly disseminated, the vascular 
strands remaining intact. Occasionally the fungus does not form 
spores in the affected panicles but causes an elongation and prolifera- 
tion of the spikelets (PL VIII). 
In maize the smut is first observed in the tassel, which sometimes is 
converted into a mass of smut; in other cases the individual flowers 
are much enlarged or deformed. Sometimes sori are not produced and 
consequently the flowers may grow out into leafy structures. The ear, 
if affected, commonly is converted into a mass of smut inclosed by the 
bracts. The rudimentary ears found on an infected plant often arc 
transformed into distorted leafy structures. When the tassel is 
Passerini, Q. Ustilago reiliana Kiihn. In Rabenhorst, Fungi Europaei Exsiccati, ed. nova, s. 2, cent. 
21, no. 20%. 1870. 
7 The original specimens collected by G. L. Clothier and J. B. S. Norton, July, 1895, Manhattan, Kans., 
are in the myeologieal herbarium of the Kansas State Agricultural College. 
