96 A Monograph of the Erysiphaceae 



Uncinula Wallrothii Lev. Ann. Sci. Nat. III. 15: 153. //. 7. 

 f. 16. 1S51 ; Cooke, Handb. Brit. Fung. 2 : 647. 1871. 



U. pntnastri (DC.) Sacc. Syll. Fung, i; 7. 1882; Wint; 

 Rabenh. Krypt. Fl. Deutschl. i^: 41. 1884; Schroet.; Cohn's 

 Krypt. FI. Schles. 3: 245. 1893; Jacz. Bull. I'Herb. Boiss. 4: 

 742. 1896; Oudem. Rev. Champ. Pays.-Bas. 2: 87. 1897. 



Exsicc. : De ThCim. Myc. univ. 1450; Cooke, Fung. Brit. 

 Exsicc. 217 ; ed. sec. 281 ; Desmaz. PI. Cr. Fr. ed. i, ser. i, 1306 ; 

 *ed. 2, ser. i, 706; Roumeg. Fung. Gall. Exsicc. 3649; Roumeg. 

 Fung. Sel. Exsicc. 4928; Rab. Fung. Eur. 2133; Syd. Myc. 

 March. 835,^3823; Fckl. Fung. Rhcn. 1747; *de Thiim. Fung, 

 austr. 463; *Sacc. Myc. Ven. 616; *Erb. Critt. Ital. ser. 2, 831 

 (cum Podosphacra oxyacanthae var. tridactyla) ; *Rab. Herb. myc. 

 ed. 2, ;^58 ; *Erikss. Fung. par. scand. 140 ; Wcstend. Herb. 

 Crypt. Belg. 969 (in Herb. Jard. bot. Bruxelles). 



Amphigenous ; mycelium evanescent ; perithecia gregarious 

 or scattered, very variable in size, from So-146/i in diameter, 

 usually about 105 /i, globose-depressed, cells about 10 // wide, 

 somewhat translucent ; appendages very variable in number, from 

 j[2-6o, 1 1^ to twice the diameter of the perithecium, rough (rarely 

 smooth) and thick-walled below, thin-walled above, colorless, asep- 

 tate, slightly enlarged upwards to a simply uncinate apex measur- 

 ing about 18/^ across; asci 7-18, ovate or elliptic-oblong, very 

 shortly stalked, 42-58 X 24-30 /-«; spores 5-7, 16-20 x 8-10/^. 



Hosts. —Pruniis insititia, P. pumila, P. spinosa \ Crataegus 

 (338)]- 



Distribution. — Europe : Britain, France, Belgium, Nether- 

 lands (263), Germany, Switzerland (176), Italy, Austria-Hungary, 

 Denmark, Norway, Sweden. 



[Asia: Transcaucasia (338)]. 



A very variable species in the size of the perithecium and 

 number of the appendages. When the latter are few, U. pnumstri 

 recalls, by the rough base and enlarged apex of the appendages, 

 U. clandestina, but that species is distinct in the 2-3-spored asci ; 

 when the appendages are numerous the present species approaches 

 U. salicis, to which, of the European members of the genus. It is 

 most allied, differing in the smaller perithecia and asci, the thick- 

 walled and nearly always rough base of the appendages, and the 

 smaller, usually 6-spores. The real affinity of U. prunastri is, 

 however, with U. Ointonii fsee remarks under that <;npriV<;\ 



