Robinson . — Notes on the Genus Taphrina . 175 
having been found on Quercus alba , L., and 0 . tinctoria , Bart., 
at New London, Conn. (Dr. Farlow) ; on < 2 . coccinea , Wang., at 
Stoughton, Wis. (Prof. Trelease) ; on g. rubra, L., at Bald 
Cap Mt. (3000 ft), N. H., also at Ithaca, N. Y. (Prof. Tre- 
lease) ; on < 2 . aquatica , Catesby, and 0 . laurifolia , Michx., at 
Green Cove Spring, Fla. (the late Dr. Geo. Martin) ; and on 
Q. cinerea , Michx., at Aiken, S. C. (Ravenel’s Fung. Amer. 
No. 72). The fungus appears on the leaves of its host during 
June in roundish spots, which vary in size, and are grey or 
somewhat bluish in colour. On the leaves of Q. rubra , which 
I have examined, these spots were pretty definite in outline, 
and only 2-5 mm. in diameter ; on Q. tinctoria , on the other 
hand, they were 10-12 mm. in diameter, and irregular in 
shape. The habit of the asci in regard to the side of the leaf 
upon which they are developed does not seem to be uniform 
on the different hosts. In his original description of Ascomyces 
caerulescens , cited above, Desmaziere speaks of the asci as 
‘ hypophyllus,’ and that undoubtedly is their usual position, 
but upon the leaves of Q. tinctoria I have found them only on 
the upper surface. In general form the asci somewhat resemble 
those of T. aurea , but their rootlike processes are generally 
shorter and penetrate the interstices of the epidermis to a less 
depth than in that species. The asci may furthermore have 
two or even three of these processes, which, in that case, are apt 
to be short and blunt. In length the asci are 55—78 /x, and in 
thickness 18-24 ^ The spores, like those of the preceding 
species, are very numerous, minute, and bacteria-like. 
By the kindness of Dr. Farlow I have had an opportunity to 
examine some of the original material of Ascomyces Quercus , 
Cooke, which was distributed as No. 72 in RaveneBs Fungi 
Americani. This parasite, which occurs on the leaves of 
Q. cinerea , corresponds perfectly, so far as I can see, with 
T. caerulescens , not only in the extent and shape of the spots 
in which it occurs, but in the size and form of the asci, which 
in both forms are polysporic. The only difference that I could 
find was in the size and shape of the spores. In Ascomyces 
Quercus they are oval in form, and vary in size from 4 fs 
