TAXONOMIC CHARACTERS OF ALTERNARIA AND MACROSPORIUM 457 
were the only plants used. No spots were formed on cabbage leaves. 
All inoculations on Dianthus were successful. In air of natural 
humidity the spots remained very small but under a bell jar they 
spread rapidly, produced concentric rings of dark spores on the surface 
and finally killed the plants. 
A. iridicola from iris leaf spots: Inoculations were made entirely 
by means of needle pricks. Both spores and mycelium were used' 
The plants inoculated were: Iris, Lilium philadelphicum L., Datura, 
potato, cabbage, Lactuca, cantaloupe, and onion (Allium cepa L.). 
All inoculations except those on iris and onion failed. Spots on iris 
extended slowly, on onion tops more rapidly, accompanied by the pro- 
duction of a considerable number of spores. Inoculations were made 
on Datura, potato, cabbage, and cantaloupe because of the general 
similarity of the spores of A. iridicola and A. solani (Plate XX, Fig. 7). 
A. sonchi from leaf spots on Sonchus asper: The fungus could not 
be isolated from the spots on Sonchus asper since the spores would not 
germinate in culture. Crude inoculations were made on Lactuca 
canadensis, using as the inoculum diseased leaf fragments of 5. asper. 
These inoculations were successful and the production of spores on 
L. canadensis abundant. Pure cultures were obtained from L. 
canadensis leaf spots. Inoculations were made, by needle pricks and 
on the unbroken leaf surface. Inoculations were made on Lactuca 
canadensis, L. saliva L., Taraxacum officinale Weber, cabbage, tomato, 
and Datura. Spots were formed only on the Compositae. On L. 
canadensis very rapidly spreading characteristic dark brown spots were 
formed in two days. On cultivated lettuce and dandelion, distinct 
spots were formed around needle-prick inoculations, but soon ceased 
to grow and no spores were produced. Spore production was abundant 
on L. canadensis. (Plate XX, Fig. 8). 
Macrosporium sarcinaeforme from leaf spots on red clover: Inocu- 
lations were made with spores, both on the unwounded leaf surface 
and by needle pricks. Red clover (Trifolium pratense), white clover 
{T. repens L.), alfalfa (Medicago sativa L.), cow pea {Vigna sinensis 
Endl.),, Cucumis melo, and Allium, were inoculated. The fungus was 
actively parasitic only on the clovers and alfalfa. Spots developed 
most rapidly on red clover and spores scattered the disease over the 
entire plant. On white clover and alfalfa the spots did not spread to 
leaves that had not been inoculated. In all cases the spots appeared 
within three days of inoculation. On onion, small white spots were 
