12 BULLETIN 1284, U. S. DEPARTMENT OF AGRICULTURE 
Endothlaspis sorghi Sorok. — Sorokine (106) has described this 
species from a collection made on sorghum in central Asia. Accord- 
ing to his description the membrane or pseudoperidium is composed 
of large spherical cells. The spores are spherical or irregular, verru- 
coses and measure 7 to 10 ju in diameter. The species is very closely 
related to Sphacelotheca sorghi (Link) Clinton, if not identical with it. 
CLASSIFICATION OF THE SORGHUMS 
As already noted, the sorghums constitute a highly diversified 
group of plants. However, from the agronomic standpoint they may 
be arranged in five divisions: 
(1) Perennial sorghum, including Johnson grass. 
(2) Grass sorghum, including Sudan grass, Tunis grass, tabucki 
grass, toura grass, and Kamerun grass. 
(3) Broomcorn, largely grown for the brush used in making brooms, 
though the stems and leaves have some value as fodder. 
(4) Sorgo, or saccharine sorghum, grown mainly for forage and to 
a less extent for sirup. 
(5) Grain sorghum, grown mostly for grain; some of them, es- 
pecially the kafirs, are also valuable as forage plants. This group 
includes the kafirs, durras, milos, feterita, kaoliangs, and shallu. 
Ball (3) has made extensive studies of the varieties of sorghums 
which have been introduced into this country and has suggested 
a system of classification in which he recognizes seven groups. Two 
of these correspond to the agronomic classification, namely, broom- 
corn and sorgo. The remaining five groups are agronomically 
classified as grain sorghums; these are durra, milo, kafir, shallu, and 
kaoliang. In addition to these, another group must be added to 
include the grass sorghums (86), such as Sudan grass. 
In presenting the results obtained in the inoculation experiments 
with kernel smut, the data on each of the seven groups of the sorghums 
proposed by Ball are reported separately. The data on Sudan grass 
are included with those of the sorgos. The results with various 
miscellaneous forms, mostly hybrids between members of the other 
groups, are reported under the heading " Miscellaneous sorghums." 
LOCATION OF THE EXPERIMENTS 
The senior writer began his experiments with the covered kernel 
smut of sorghum at Columbia, Mo., in 1915, while botanist at the 
Missouri Agricultural Experiment Station. The investigations were 
continued there in 1916, 1917, and 1918. From October 1, 1918, to 
December 31, 1920, he was pathologist in charge of cereal-smut 
investigations in the Office of Cereal Investigations, Bureau of Plant 
Industry. 
The junior writer, in cooperation with A. A. Potter, formerly of 
the Office of Cereal Investigations, Bureau of Plant Industry, con- 
ducted experiments at the Kansas Agricultural Experiment Station, 
Manhattan, Kans., and the Cereal Field Station, Amarillo, Tex., 
from 1916 to 1918. 
The investigations were continued jointly by both writers at 
Amarillo in 1919, at Manhattan from 1919 to 1921, at the Arlington 
