10 BULLETIN 1284, U. S. DEPARTMENT OF AGRICULTURE 
for considerable periods of time, only a few germinating periodically. 
The evidence of Potter points also to the fact that infection takes 
place through the young sprout. Rarely do slightly older plants 
become infected. 
SORGHUM SMUTS NOT KNOWN TO OCCUR IN THE UNITED STATES 
Tolyposporium filiferum Busse. — This smut was described first 
from East Africa in 1904 by Busse (20) , who found it on sorghum at 
various points in Tanganyika Territory, where apparently it caused 
no great damage. It is probable that Barber (8) referred to this 
smut as one of the three which occurred in the Madras Presidency. 
In his description, the pathological symptoms coincide with those 
produced by this fungus, although he attributed the cause to Ustilago 
reiliana. Kulkarni (63) reports the occurrence of this smut, de- 
scribed as "long smut," in the Bombay Presidency, stating that it 
is mostly confined to Sind but also occurs sparingly in the Kathiawar 
States. In restricted areas it may cause considerable loss, but in 
the Bombay Presidency as a whole the damage is comparatively 
insignificant. Butler (21) mentions its occurrence in the Madras 
Presidency and Sind. Thomas (109) refers to its occurrence in Meso- 
potamia. According to Briton- Jones (14-) it is common in Egypt. 
This smut has not been reported in the United States. 
In long smut only a few flowers of a head are infected. The 
glumes of the spikelet remain unaltered, but the ovaries are trans- 
formed into smut balls or false kernels. These false kernels are 
cylindrical, usually curved and abruptly pointed at the distal end. 
They vary from 6 to 25 millimeters in length and 4 to 6 millimeters in 
diameter. At maturity the shining grayish white membrane of the 
smut ball opens at the tip, occasionally cracking in the middle. The 
interior of the smut ball consists of a mass of smut spores surround- 
ing a bundle of 8 to 10 or more dark-brown strands of host tissue, 
usually joined at the base. These are the remnants of the fibro- 
vascular bundles. 
The spores are grouped in firm spore balls, which are irregular in 
shape and 40 to 120 n in size. The individual spores are brown, 
spherical or oblong, with echinulate walls on the free side. They 
vary in size from 8 to 14 /x in diameter. They germinate readily in 
water and in various nutrient solutions. The promycelium is some- 
times branched, generally three celled, and bears sporidia apically 
and laterally at the septa, frequently in clusters. The sporidia in 
turn produce secondary spores by budding or grow out into long 
tubes. Branching chains of aerial sporidia are formed at the surface 
of a culture. 
It is not known how infection occurs. Seed treatments appear to 
be of no value in preventing the disease, and this would seem to indi- 
cate that seed-borne spores are not the source of infection. It 
remains to be determined whether individual flowers are infected 
by the air-borne secondary sporidia or whether seedling infection 
takes place from spores present in the soil. 
Tolyvosporium volkensii P. Henn. — This sorghum smut was de- 
scribee! by Hennings (32, p. 48-49) from specimens sent by Volkens, 
who collected them in Kilimanjaro, East Africa. The smut was 
