650 MINNESOTA BOTANICAL STUDIES. 



several species, one a Torula, but the rest included in Oospora 

 by Saccardo. There would seem to be no reason why Alysidium 

 should not be preferred even by those who would restrict the 

 rule of priority by a year-limitation. 



The species reported from the United States to be included 

 in the genus as here limited are: 



Alysidium albipes (Pk.) 



Oidium albipes Pk. Rep. N. Y. Mus. 30:— (57). 1878. 

 Alysidium candidulum (Sacc.) 



Oospora candidula Sacc. Mich. 2:545. 1882. 

 Alysidium compactum (C. & E.) 



Oidium compactum C. & E. Grev. 6:5. 1877. 

 Alysidium cuboideum (Sacc. & Ell.) 



Oospora cuboidea Sacc. & Ell. Mich. 2: 576. 1882. 

 Alysidium cuccmeris (Pk.) 



Oospora cucumeris Pk. Rep. N. Y. Mas. 41:— (80). 1888 

 Alysidium fasciculatum (Grey.) Pound & Clements Bot. Surv. Nebr. 4:37. 1896. 



Acrosporium fasciculatum Grey. Fl. Ed. 469. 1824. 



Oidium fasciculatum Berk. Smith's Engl. Fl. 5: 349. 1836. 



Oospora fasciculata Sacc. & Vogl. Syl. Fung. 4: 11. 1886. 

 Alysidium folvum Kunze, Myk. Heft. 1:18. 1817. 



A.LYSIDIUM HYALINULUM (SACC.) 



Torula hyalinula Sacc. Mich. 1:538. 1879. 



Oospora hyalinula Sacc. Mich. 2: 453. 1882. 

 Alysidium insulare (Thuem.) 



Torula insularis Thuem. Flora 61:— (6). 1878. 

 Alysidium lactis (Fres.) 



Oidium lactis Fres. Beitraege 23. PL 3 f. 41. 1850. 

 Alysidium ovalisporum (Berk.) 



Tonda ovalispora Berk. Smith's Engl. Fl. R: 359. 1836. 

 Alysidium pallidum (B. & Rav.) 



Torula pallida B. & Rav. Grev. 3: 14. 1873. 

 Alysidium pulvinatum (B. & C.) 



Oidium pulvinatum B. & C Grev. 3:112. 1875. 



Alysidium tulipiferae (E. & M. i 



Oospora tulipiferae E. & M. Am. Nat. 16: 1004. 1882. 



9. FUSIDIUM Lk. Obs. 1 : 6. 1809. 

 Sporophores short, simple; conidia fusiform, concatenate, 

 hyaline or light-colored. 



2 species are reported from the United States. 



10. CYLINDRIUM Bon. Handb. Alg. Myk. 34. 1851. 



Mycelium scanty or none; sporophores very short, scarcely 

 or not at all distinct from the conidia; conidia long-cylindrical, 

 obtuse at the ends, concatenate, the chains of conidia simple or 

 branched, hyaline or light-colored. 



2 species are reported from the United States. 



