278 
Journal of Agricultural Research 
Vol. XXXI, No. 3 
to find seed of wild species netted two or three species which did not 
germinate. Somewhat better success was had in Europe and most 
of the seed which the writer has obtained came from Kew Gardens, 
Haage & Schmidt, of Erfurt, Germany, H. Zillig, of. Trier, Germany, 
and Vilmorin-Andrieux & Co., at Paris. Only last summer did the 
writer succeed in getting seed (or bulblets) of all the three native 
New England species of Allium. Allium seed seems to lose its 
vitality very rapidly, and seed more than a year or two old frequently 
can not be made to germinate. The writer thinks it is possible, of 
course, that he has not been able always to provide in the plots the 
special conditions which may be necessary to bring some species to 
germination. Altogether seed of about 100 species has been tried 
and the seed of only 39 have germinated. 
In the course of this work it has been observed that there are 
gradations in the severity of infection. On this basis all the species 
may be divided into the following classes: 
Class 1. Most susceptible class. Sori first appear in the cotyle¬ 
dons and may of the plants die at this time. Those which survive 
may slough off the disease, or lesions may appear in the successive 
true leaves, ending in the final death of the plant before it forms seeds. 
Class 2. Less susceptible than class 1. Smut sori occur only in the 
cotyledons, and many plants die in this stage, but if they survive no 
lesions appear in the true leaves. 
Class 3. Species harely susceptible in that smut sori may be found 
in the cotyledons, but the plants are not killed in this or later stages 
and no sori appear in the true leaves. 
Class 4: Entirely resistant species in which smut lesions have not 
been observed in any of the parts. 
In infested soil from the same field three different plantings were 
made. Nineteen species were planted May 1, 1923 in flats kept out 
of doors; 40 species in a greenhouse bench on October 11, 1923; 
and 64 species in an outdoor bed on April 25, 1924. Some species 
were tested in all three plantings, some in two, and some in only one, 
depending on the supply of seed and the need of further testing. In 
cases where fewer than 100 plants came up this fact is mentioned in 
the following notes on the individual species. 
f 
CLASS 1 
Allium Cepa L., to which all our varieties of cultivated onions 
belong, is typical of Class 1. All infection seems to take place through 
the cotyledon. A large percentage of infected plants die in this stage. 
If no sori occur in the cotyledon, none will be found in the true leaves 
which follow. Sometimes, even when the cotyledon is affected, the 
fungus fails to gain entrance into the growing point and no lesions 
will be found in the following leaves. In the latter case, the bulb 
and seed are developed normmly. More often, however, the parasite 
gets into the growing point and each successive leaf will have spore 
sori, in which case the leaves are short, distorted, and brittle, and the 
dwarfed plants die in various stages of development' throughout the 
summer. Some of them form bulbs as large as an inch in diameter 
with longitudinal black spore pustules in the outer scales, but they 
usually rot before they are harvested. It is doubtful whether a 
plant which has spores in the first leaf ever recovers. In the soil 
