70 PEOCEEDINGS OF THE AMERICAN ACADEMY 



in several of the species which also occur in Europe, is in my opinion 

 undesirable. To group together hastily different forms is a very easy 

 matter ; but it is more to one's credit to be willing to wait until future 

 study shall have shown what forms really are connected. 



Syncliytrium fulgens Schrt. var. decipiens Farlow, no. 201, and 

 S. Anemones Wor., no. 203, are now known to be common in the 

 Western as well as the Eastern States, but apparently *S'. papillatum 

 Farlow is not known beyond the region where it was first collected 

 by Dr. Anderson. 



No. 207, Peronospora ohducens Schrt., has also been found in Iowa 

 by Professor C. E. Bessey, and in Illinois by Mr, A. B. Seymour. 

 I at first su^jposed that this fungus appeared only in the spring on the 

 cotyledons and occasionally the youngest leaves of Impatiens, but it 

 was found by Professor William Trelease to be common ou the mature 

 leaves of Impatiens collected at Wood's Holl in August, 1880. The 

 cotyledons are generally thickly covered by the conidia, but on the 

 leaves the spots are generally small and scattered. I have myself 

 never found ripe oospores, and only rarely the young oospores, of this 

 species, but they were found fully developed by Mr. Seymour in 

 specimens on Impatiens collected in Illinois. They occur in large 

 numbers in the petioles and young stems from just beneath the 

 epidermis to near the vascular bundles. The oogonia measure from 

 38-45/x in diameter, and the oospores themselves are from 26-31/a 

 in diameter, with an endospore about 3/x thick. The outer wall of 

 the oospores is nearly smooth, but usually has a few ill-defined folds 

 or ridges, not, however, to be compared with the markings on the 

 oospores of some other species. 



No. 208, Peronospora viticola (B. «&; C.) De Bary. In the Bussey 

 Bulletin, Vol. I. p. 422, March, 1876, I made the statement that 

 practically no harm was done to the grape crop in our Northern States 

 by this fungus, but added, " Should the fungus be introduced into 

 Central Europe, the case might be different." Since that date, as 

 every one knows, this parasite has been introduced into Europe, and 

 an enormous amount has been written relating to its spread on 

 the Continent and the harm that it has caused. On the latter point 

 authorities differ, some going so far as to assert that it does as much 

 harm as the Phylloxera, and others that it does perceptible harm 

 only in exceptionally moist seasons. The majority of writers, how- 

 ever, believe that considerable damage is done by the fungus, and the 

 statement made in the Bussey Bulletin is not credited. While admit- 

 ting the damage done in other regions, I have seen no reason for 



