TAUBENHAUS: SILVER SCURF OF THE WHITE POTATO 553 



the former are either abortive, imperfectly developed, or not very 

 abundant. It will be readily seen, therefore, why Frank was led 

 to create the new genus Phellomyces, and overlooked its resem- 

 blance or relationship to the genus Colletotrichum. Moreover, 

 Frank's Phellomyces is not a sterile fungus, since it produces 

 Colletotrichum-Vike spores. Hence, the genus Phellomyces is not 

 valid. 



Recently the writer (20) described the charcoal rot of sweet 

 potatoes, which is attributed to the fungus Sclerotium bataticola 

 Taub. This organism greatly resembles Phellomyces. However, 

 it produces neither setae nor spores but sclerotia only. Hence 

 the writer placed this fungus in the genus Sclerotium. It matters 

 little whether sclerotia are minute or large, free or buried in the 

 tissue; as long as they are sterile bodies, they should be placed 

 in the genus Sclerotium. In such cases, the less genera we have, 

 the better. It is evident then,- that the Phellomyces of Frank, 

 which is found associated with silver scurf, is a Colletotrichum. 

 It is probably also the same fungus as Vermicularia atramentaria 

 Berk. & Br. (1). Halsted, (3) in 1894, while working on a stem 

 blight of the white potato, met with this fungus; he says: "The 

 fungus in question seems to be Vermicularia atramentaria Berk. 

 & Br., but the amount it has to do with causing the destruction 

 of the crop is an open question." The species V. atramentaria 

 is recognized by Saccardo (8), Rabenhorst (7), and Clements (15). 

 However, the species is poorly described and no measurements of 

 spores are given. Studies were made by the writer, of the various 

 specimens of Vermicularia atramentaria found at the herbarium 

 of the New York Botanical Garden. From these studies, it 

 seemed evident that Vermicularia atramentaria is not a Vermicu- 

 laria. The bodies which may be taken for pycnidia of Vermicu- 

 laria seem to be sterile sclerotia; these may be with or without 

 black setae (figs. 19-21). The spores of V. atramentaria as 

 stated above, are not borne in the sclerotia, but in typical acervuli 

 with setae near the sclerotia (figs. 21 and 20). Of the collections 

 of Vermicularia atramentaria at the New York Botanical Garden, 

 one specimen is of particular interest. It reads as follows: 



"C. Roumegere. — Fungi Gallici exsciccati. 



"2968. Vermicularia atramentaria Bk. et Br. Fung. 



"n. 430, forma sclerotioides." 



