400 BRITISH DISCOMYCETES. 



B. The mycelium spreading only between the 

 epidermal cells and the cuticle of the 

 young shoots. 

 (a) Asci furnished with a stem-cell . . species 5-7 



0. Species the position of which is at present 



uncertain . . . . . . . . 8, 9 



KEY TO THE SPECIES. 

 On trees .. .. 1 



On herbaceous plants. . 



'On leaves of Alnn,s glutinosm : sporidia 8 



On female catkins of Alnus glutinosm : sporidia 



more than 8 . . 

 On leaves of Juglans regia 

 On branches and leaves of Betula alba 



2 

 Tosquinetii, 



Alni. 



Juglandis. 



turgidus. 



On leaves of Pyrus communis, Cratssgus Oxycantha, 



and C. monogynea . . . . . . . . . . bullatus. 



On young fruit of Prunus domestica, P. Padus, and 

 P. spinosa . . . . . . . . . . . . Pruni. 



On leaves and branches of Prunus avium, P. 

 Cerasus, P. domestica, P. Cham&cerasus, and 

 Persica vulgaris, P. amygdalus, and P. communis deformans. 

 9 (On Potent-ilia Tonnentilla . . . . . . . . Potentillaz. 



*" \On Trientalis Europgea, . . . . . Trientaltis. 



A. PERENNIAL MYCEIJUM SPREADING THROUGH THE IN- 

 TERCELLULAR SPACES OF THE YOUNG SHOOTS OF THE 

 INFECTED PLANT IN SPRING. 



(a) Asci furnished with a stem-cell. 



1. Ascomyces Pruni. (Tul.) 



On unripe fruit of Prunus domestica, spinosa, and 

 Padus, deforming them ; asci oblong-clavate, rounded or 

 truncate at the summit; sporidia 8, broadly elliptic, 

 about 6 x fyi. 



Taphrina Pruni TuL in "Ann. Sc. Nat./' ser. 5, 

 vol. v. p. 129; Johanson, "Yet. Ac. Hand!.," arg. 42, 

 p. 32. Exoascus Pruni Fckl., " Symb. Myco./' p. 252; 

 Sadebeck in Rabh., " Krypt. Flo./' p. 5, fig. 3. Ascomyces 

 Pruni B. and Br., "Ann. Nat. Hist./' No. 1629; "Gre- 

 villea," v. p. 62. 



Exs. Fckl., "F. Rh," 1081; Kunze, "Fung. Sel./' 

 167; Rabh., "Fung. Eur./' 1167; Rehm, "Asco," 130; 

 Thum., " Fung. Aus.," 504 ; Thum., " Mycoth. Univ.," 976. 



