138 Wisconsin Academy of Sciences, Arts, and Letters. 
that Eriksson himself does not believe that the experiment was 
carried out with sufficient accuracy to give absolutely certain re¬ 
sults. 
Neger offers no evidence that the ascospores actually do have 
a wider range of host-plants than the conidia of the same species. 
Salmon (10) distinctly states that he has frequently observed 
perithecia on Senecio vulgaris and Symphytum, while others 
have recorded them on Calamintha and Hieraceum, all of which 
are plants upon which Neger did not find perithecia. It is pos¬ 
sible that' with more careful observation, perithecia will be found 
on all plants on which conidia are produced. 
Marchal (7), during the spring of 1902, attempted the infection 
of several grasses with conidia of Erysiplie graminis. He gives 
no detailed account of his work but states that conidia from 
wheat would not infect rye, oats and barley; conidia from rye 
would not infect wheat, oats and barley; conidia from oats 
would not infect wheat, rye and barley; and conidia from barley 
would not infect the other cereals. As a result of his work he 
makes seven physiological species which he names as follows: 
1. E. graminis f. spec. Tritici upon T. vulgare, T. Spelta, T. 
polonicum, T. turgidum , not on T. durum, T. monococcum, T. 
dicoccum. 
2. f. spec. Hordei upon II. hexastichon, H . vulgare, II. tri - 
furcatum, II. nudum, II. jubatum, and II. murinum, not on H. 
maritimum } H, secalinum, nor H. bulbosum. 
3. f. spec. Secalis upon S. cereale and S. anatolicum. 
4. f. spec. Avenae upon A. sativa, A. fatua, A. orientalis, and 
Arrhenathcrum elatius. 
5. f. spec. Poae upon P. annua, P. trivialis, P. pratensis, P. 
caesia, P. mutalensis, P. memoralis, and P. serotina. 
6. f. spec. Agropyri upon Agropyron. 
7. f. spec. Bromi upon various Bromes. 
It is impossible to tell how far Marchal’s results are reliable 
since he gives no data as to the number of his experiments or 
the conditions under which they were performed. 
There is, in fact, considerable evidence that there are more 
than seven special forms of mildew which infect these grasses 
mentioned as hosts. 
