Fmigus vjJiich causes Powdery Mildew on Leaves of Paivpaw Plant. 189 
from the latter to the former. Phyllactinia corylea has thus far not been 
recorded from the leaves of the pawpaw, though it has a large number of 
host-plants, and Salmon* records it from mulberry {Morus alba) from Japan. 
In South Africa it has to date not been found on this host. 
We give the following brief diagnosis of the pawpaw fungus : 
OVTJLAEIOPSIS PAPAYAE, U. Sp. 
Sterile hyphae hyaline, epiphytic, penetrating interior of leaf through 
the stomata and ramifying in the intercellular spaces of the spongy paren- 
chyma ; conidiophores arising from the sterile hyphae, erect, cylindrical, 
pluriseptate, up to 200 ^i- long, 7 fd. diam. ; conidia large, borne singly at 
apex of conidiophores, subclavate, 60-90 x 14-23 fi, majority 72 x 14 /x ; 
conidiophores and conidia usually smooth, rarely beset with fine projections. 
Habit. — On under-surface of live leaves of Carica ^jajjaya, causing 
" powdery mildew." Common along Natal coast. (Type in Natal Her- 
barium, P. V. d. B., No. 924.) 
* Salmon, E. S., " The Erysiphaceae of Japan/' ' Bull. Torr. Bot. Club,' xxvii, 
pp. 438-439, 445 (1900). 
