402 BRITISH DISCOMYCETES. 



No. 2232; Gill., "Champ.," p. 201. Oidium bullatum 

 — B. and Br., "Jour. Hort. Soc," ix. p. 51, with 

 fig. Taphrina bullata — Tul., " Ann. Sc. Nat.," ser. 5, 

 vol. v. p. 127; Johanson, "Vet. Ac. Handl.," 42, p. 33. 

 Exoascus bullatus — FckL, " Symb. Myco.," nacht. ii. p. 49 ; 



Exs.— FckL, "F. Rh.," 2551; Thum, "Fung. Aus," 

 972 and 1056. 



On living pear-leaves. It also occurs on Crataegus 

 Oxycanthus, and C. monogyna. April and May. 



The asci are 30 — 37 X S/u ; the sporidia 45/z (Sade- 

 beck, I. c). Asci 15 — 25 x 10^ (Cooke, I. c). 



Name — Bullata, a blister ; blistered. 



Shrewsbury ! 



(b) Asci not furnished with a stem-cell. 



4. Ascomyces Potentillce. (Farlow.) 



Decolorizing (to pale yellow-green) the branches and 

 leaves, rendering the branches several times thicker than 

 their natural size ; asci clavate, rounded or truncate at 

 the summit, attenuated below into a slender, non-septate 

 stem, continuous with the mycelium, which spreads 

 through the intercellular spaces of the epidermis ; sporidia 

 8, oblong-elliptic, 5 — 8 X i/u. 



Exoascus deformans, var. Potentillce — Farlow, " Proc. 

 Am. Ac. A. and S.," xviii. (1883), p. 84. Taphrina 

 Tormentillce— Host., " Bot. Tid.," ser. 3, vol. iv. (1884- 

 1885), p. 239; Johanson, "Vet. Ac. Handl," 42 (1885), 

 p. 29, t. 1, f. 2. 



On Potentilla Tormentilla, Scop. 



The asci in the Scottish specimen are truncate or 

 rounded at the summit, and attenuated downwards more 

 or less equally to a slender stem-like base, arising 

 directly from the branching hyphse beneath the cuticle, 

 30 to 50/x high, 7 to 9/i in the broadest part, and 2/z in 

 the narrowest part. The sporidia are confined to the 

 broad upper half of the ascus, elliptic, and (as I measure 

 them) 4 — 5 x 2— 2 5^. 



