ERYSIPHALES 111 



species of Helminthosporium, several of \\hich, as Drechsler 

 (1923) established, are genetically related to Pyrenophora. 



LITERATURE CITED 



BiTANcouRT, A. A., AND A. E. Jenkins, ''Elsiuoe fcTivcetti, the perfect stage 

 of the citrus-scab fungus," Phytopathology, 26: 393-396, 1936. 

 "Sweet-orange-fruit scab caused by Elsinoe mistralisj'^ J. Agr. Research, 

 5^:1-18, 1937. 

 BuRKHOLDER, W. H., "The anthracnose disease of the raspberry and re- 

 lated plants," Cornell Agr. Expt. Sta. Bull., 395: 157-183, 1917. 

 "The perfect stage of Gloeosporhnn Venetian,''' Phytopathology, 7; 83-91, 

 1917a. 

 Drechsler, C, "Some graminicolous species of Helminthosporium, I," /. 



Agr. Research, 2-/; 641-740, 1923. 

 Jenkins, A. E., "Lima-bean scab caused by Elsinoe," /. Agr. Research, 42: 

 13-23, 1931. 

 "Elsinoe on apple and pear," /. Agr. Research, 44: 6S9-7 00, 1932. 

 ''''Sphaceloma perseae, the cause of avocado scab," /. Agr. Research, 49: 

 859-869, 1935. 

 Miller, J. H., "Studies in the development of two Myriangium species and 

 the systematic position of the Myriangiales," Mycol., 30: 158-181, 1938. 

 Theissen, F., "Studien iiber Botryosphaeria," Ami. Mycol., 14: 297-340, 1916. 

 Wolf, F. T., and F. A. Wolf, "A study of Botryosphaeria ribis on wil- 

 low," Mycol, 31:1X1-111, 1939. 

 Woroninchin, N. N., ^'Plectodiscella piri, der \^ertreter eines neuen 

 Ascomyceten-Gruppe," Mycol. Centrb., ^; 225-233, 1914. 



Erysiphales 



Among the Erysiphales, also called the Perisporiales, are two 

 important families: Erysiphaceae, or po\ydery milde\\s, and 

 MeHolaceae (Perisporiaceae), or sooty molds. Essentially all are 

 limited in habitat to the surface of green plants, and none appears 

 to have been cultivated on artificial media. Their ascocarps are 

 cleistothecia in which the asci are arranged in an orderly layer, 

 rather than being dispersed as in the Eurotiales. 



Erysiphaceae. The powdery mildew^s, except Erysiphe graiiii- 

 nis on various grasses, are limited in host range to dicotyledonous 

 angiosperms. The monograph of Salmon (1900) lists 49 species 

 and 11 varieties, occurring on about 1500 host species. Many 

 of those listed in Saccardo's Sylloge Fiingorinn have been re- 

 duced to synonymy by Salmon. Six genera, Erysiphe, Micro- 



